Tychos Python Language Reference

The following reference guide identifies the language syntax, built in variables, functions, and classes that are used to code your simulations using the Python Language. We have included documentation here for some of the helpful functions defined in the Python language. This is not a complete list of all functions available in Python, just ones that might be commonly used in Tychos for building scenarios as well as defining goals for those scenarios.

Comments

Comments are statements that you can insert in your code that do not get interpreted and executed by Tychos. To create a comment, you simply indicate a comment by using a hashtag:

# This is a comment.

Variables

To define a variable in Tychos all you need to do is identify a name for the variable. You then type an = sign to assign a value to the variable. The following demonstrates various variable declarations

# Assigns a variable called x the value of 10
x = 10
# Assign a new variable y the value of the x
y = x
# Assign x the value of itself plus 1
x = x + 1

Built-in Scenario Variables

There are a few variables that are built into Tychos. These variables are:

  • t — How many seconds has passed since this Scenario was started?

  • dt — Time between frames as seconds, e.g. 0.1 is 1/10th of a second.

  • frame_count — How many frames have passed? e.g. 1, 2, 3...

Common Math Operators and Functions

These are some common mathematical operators and functions for performing various calculations.

Mathematical Operators

Tychos uses the following operators to perform basic math calculations:

  • + — Addition

  • - — Subtraction

  • * - Multiplication

  • / - Division

  • ** - Exponent

  • % - Modulo

Basic Math Functions

You can also use the following basic math functions:

sqrt(positive_number)

The sqrt(positive_number) function takes a single non negative number and returns the real square root of the number.

# returns number 2
sqrt(4)

exp(power)

The exp(power) function calculates Euler's number (e) to the given power.

# returns 54.59815
exp(4)

log(x)

The log(x) returns the natural log (base e) of x.

# returns number 2
abs(-2)

ceil(x)

The ceil(x) function rounds a number up to the nearest integer.

# returns 5
exp(4.1)

floor(x)

The floor(x) function rounds a number down to the nearest integer.

# returns 4
exp(4.9)

sign(x)

The sign(x) function returns +1 if x is less than 0, -1 if x is greater than 0, and 0 if x is equal to 0.

# returns -1
sign(-42)
# returns 1
sign(42)
# returns 0
sign(0)

abs(x)

The abs(x) function returns the absolute value of a number.

# returns number 2
abs(-2)

random()

The random() function returns a semi random number between 0 and 1.

x = random()

randrange(a, b)

The randrange(a,b) function returns a semi random number between a and b.

x = randrange(10, 100)

factorial(x)

The factorial(x) function calculates the product of all positive integers less than or equal to the given positive integer.

# x! = x*(x-1)*(x-2)....(1)
# returns 120
factorial(5)

combin(n, r)

The combin(x,y) function calculates the number of ways to choose a sample of r elements from a set of n distinct objects where order does not matter and replacements are not allowed.

# x!/(y!*(x-y)!)
# returns 10
combin(5,2)

Trigonometric Functions

The following functions all use radians as the angle measurement. You can use pi to represent PI.

sin(angle)

The sin(angle) function is used to evaluate the trigonometric sine value for a given input angle. The input angle must be provided in radians.

# returns number 1
sin(pi/2)

cos(angle)

The cos(angle) function is used to evaluate the trigonometric cosine value for a given input angle. The input angle must be provided in radians.

# returns number 1
cos(0)

tan(angle)

The tan(angle) function is used to evaluate the trigonometric tangent value for a given input angle. The input angle must be provided in radians.

# returns number 1
tan(pi/4)

asin(value)

The asin(value) function is used to evaluate the trigonometric arcsine value (inverse sine) for a given input. The output angle is given in radians.

# returns number 1.57
asin(1)

acos(value)

The acos(value) function is used to evaluate the trigonometric arccosine value (inverse cosine) for a given input. The output angle is given in radians.

# returns number 0
acos(1)

atan2(x, y)

The atan2(value) function is used to evaluate the trigonometric arctangent value (inverse tangent) for a given x and y input. The output angle is given in radians.

# returns number -0.785
atan2(-1, 1)
# returns 2.36
atan2(1, -1)

radians(angle)

The input is an angle measurement in degrees and the output is the angle measurement in radians.

# returns number .785
radians(45)

degrees(angle)

The input is an angle measurement in radians and the output is the angle measurement in degrees.

# returns number 180
degrees(pi)

Vector and Vector Functions

The following functions provide operations for creating and using vectors in calculations.

vec(x, y), or vec(x,y,z)

Creates a Vector object representing a 3d vector with components identified as x, y, and z.

# Create a vector with components x=2, y=2, z=0
v1 = vec(2,2)

# Create a vector with components x=2, y=2, z=2
v2 = vec(2,2,2)

# Change a component of the vector:
v1.x = 3

Adding and Subtracting Vectors

Vectors can be added or subtracted from one another using standard +, - operators:

v1 = vec(2,2)
v2 = vec(1,1)

# Add the two vectors together:
v3 = v1 + v2 # Returns vec(3,3,0)

Multiplying and Dividing By A Scalar

Vectors can also by scaled using the standard *, / operators:

v1 = vec(2,2)

# Multiply by a scalar
v2 = 2 * v1 # Returns vec(4,4,0)

# Divide by a scalar
v3 = v1 / 2 # Returns vec(1,1,0)

dot(v1, v2)

Calculates the dot product of two Vector objects.

# Work is the dot product of Force (F) and displacement (r)
F = vec(2, 2)
r = vec(3, 3)
# returns 12
Work = dot(F, r)

cross(v1, v2)

Calculates the cross product for two vectors in three dimensional space.

# Torque is the cross product of Force and moment arm (r)
F = vec(2, 0, 0)
r = vec(0, 2, 0)
# returns Vector vec(0, 0, 4)
cross(F, r)

norm(vec)

Same as hat. See below.

hat(vec)

This function returns a unit vector representation of the given input vector. Its magnitude is 1 and the direction matches the direction of the input vector. This can be useful if you need just the direction of a vector, but not its magnitude.

  • vec - any two or three dimensional vector.

Example:

u = hat(vec(3, 4))  # returns vec(0.6, 0.8, 0)
mag(u)             # returns 1

mag(vec)

This function returns the scaler magnitude of any given vector. This is helpful when you want to know the length of a vector, for example, if you want the magnitude of a vector, but not the direction.

  • vec - any two or three dimensional vector.

Example:

mag(vec(3, 4))             # returns 5

mag2(vec)

This function returns the scaler squared magnitude of any given vector.

  • vec - any two or three dimensional vector.

Example:

mag2(vec(3, 4))             # returns 25

diff_angle(vec1, vec2)

This function returns the angle between two vectors. The angle is returned in radians.

  • vec1 - any two or three dimensional vector.

  • vec2 - any two or three dimensional vector.

Example:

# returns 0.7853981633974484
diff_angle(vec(4, 4), vec(4, 0))

diff_angle(vec1, vec2)

This function returns the angle between two vectors. The angle value is returned in radians.

  • vec1 - any two or three dimensional vector.

  • vec2 - any two or three dimensional vector.

Example:

# returns 0.7853981633974484
diff_angle(vec(4, 4), vec(4, 0))

proj(vec1, vec2)

This function returns the vector projection of vec1 along vec2.

  • vec1 - any two or three dimensional vector.

  • vec2 - any two or three dimensional vector.

comp(vec1, vec2)

This function returns the scalar projection of vec1 along vec2.

  • vec1 - any two or three dimensional vector.

  • vec2 - any two or three dimensional vector.

distance(point1, point2)

This function returns a scalar quantity representing the distance between two points.

  • point1 - any two or three dimensional vector representing a point in space.

  • point2 - any two or three dimensional vector representing a point in space.

Example:

distance(vec(5,5), vec(3,3))            # returns 2.8284271247461903

direction(vec)

This function returns a scalar angle measurement. This is helpful when you want to know the direction of a vector, like the direction of a velocity vector, or the direction of a force vector. The returned angle is given in radians, measured from the positive x axis.

  • vec - any two or three dimensional vector.

Example:

direction(vec(4, 4))             # returns 0.7853981633974483

polar(radius, angle)

This function returns a two-dimensional vector representing the cartesian components of a polar coordinate corresponding to the magnitude of the radius and the radial angle.

  • radius - scalar quantity representing the scalar distance of the radius of the

  • angle - scalar quantity representing the angle measurement of the polar coordinate.

Example:

polar(10, pi/4)            # returns vec(7.07, 7.07, 0)

get_rotated_position(position, angle, axis)

This function is simply used for finding a point that has been rotated a given angle about a specific axis. It is just a utility function that could be performed by doing some simple trigonometry calculations, but hey, why not make it easier for you?

  • position - A vector representing the point that is rotated.

  • angle - scalar quantity representing the angle measurement of rotation.

  • axis - A 2D vector that identifies the axis point about which the position has been rotated.

Example:

get_rotated_position(vec(10, 0), pi, vec(0, 0))            # returns vec(-10, 0, 0)

Other Useful Functions

Some other useful functions..._

rgb(r, g, b)

This function returns a hexadecimal value for the red, green, and blue input values. This can be useful for setting the color of an object based on the RGB color model.

  • r - a value between 0 and 255 representing the RED of RGB.

  • g - a value between 0 and 255 representing the GREEN of RGB.

  • b- a value between 0 and 255 representing the BLUE of RGB.

Example:

color = rgb(100, 100, 0)            # returns '#646400'

stop()

This function interrupts the simulation and stops it at the current frame.

stop() -> stops the simulation.

Example:

if buggy.pos.x > 100:
    stop()             # simulation stops

Collision Functions

Currently circle ,rectangle , and line objects work with any of the collision functions. We are working to add other objects soon.

The following functions are meant to help users model collisions more easily. These functions could be used for other purposes rather than modeling collisions as Tychos is not a physics engine. These functions could be thought of as "overlap" functions. They return information about the overlap of objects.

has_collided(source, target)

This function returns a boolean true/false value when two objects are given as the source and target. It returns false if the two objects are not determined to be overlapping.

  • source - circle or rectangle or line object

  • target - circle or rectangle or line object

Example:

# Initial State
p1 = circle(pos=vec(15, 0), radius=10, color=rgb(0, 200, 200), opacity=.6)
b1 = rectangle(pos=vec(0, 0), size=vec(15, 15), color=rgb(200, 0, 200), opacity=.6)
b1.rotate(radians(45))
p3 = circle(pos=vec(-15, 0), radius=10, color=rgb(0, 0, 200), opacity=.6)
# Calculations
has_collided(p1, b1)            # returns True
has_collided(b1, p3)            # returns True
has_collided(p1, p3)            # returns False

get_mtv(source, target)

This function returns a two dimensional vector representing the minimum translation vector (MTV) that would be needed to separate two objects when they overlap. This can be used to simulate collision forces or to move objects apart based on the magnitude and direction of the MTV.

  • source - circle or rectangle or line object

  • target - circle or rectangle or line object

Example:

# Initial State
p1 = circle(pos=vec(0, 0), radius=10, color=rgb(200, 200, 200), opacity=.6)
p2 = circle(pos=vec(12, 10), radius=10, color=rgb(0, 200, 0), opacity=.6)
b1 = rectangle(pos=vec(-12, 0), size=vec(15, 15), color=rgb(200, 0, 0), opacity=.6)
mtv1 = arrow(pos=p1.pos, color="green")
mtv2 = arrow(pos=p1.pos, color="red")
# Calculations
mtv1.size = get_mtv(p1, p2)
mtv2.size = get_mtv(p1, b1)

get_intersections(source, target)

This function returns a list containing all the points where the object boundaries intersect. The points are vectors corresponding with the coordinates of those intersection locations. This can be used to identify exactly where the overlap is occurring in your scenarios.

  • source - circle or rectangle or line object

  • target - circle or rectangle or line object

The image below shows an example of the points of intersection between a rectangle and a line, but note, those points are being showed for demonstration only, and would not be visible unless you assign them to a visible object, in this case the position of two small circle objects.

Example:

# Initial State
r = rectangle(pos=vec(-4, 0), size=vec(10,15), color="orange", opacity=.5)
r.rotate(.1)
l = line(pos=vec(0,10), pos2=vec(-10, -20))
# Calculations
points = get_intersections(r, ln)

Logical Operators

The following operators are used to execute logical AND and OR comparisons for the use of evaluating logical statements.

and

This is used for performing a logical AND conjunction. For example, "A and B" is true only if A is true and B is true. "A and B" is false if either A or B is false.

A = True
B = True
A and B         # returns true
B = False
A and B         # returns false

You can use the and operator to test if two comparisons are both true:

x = 2
(x < 3) and (x == 2)  # returns True
(x < 3) and (x != 2)  # returns False

or

This is used for performing a logical OR conjunction. For example, "A or B" is true if A or B is true. "A or B" is false only if A and B are both false.

A = True
B = False
A or B # returns True
A = False
A or B # returns False

You can use the or operator to test if one of two comparisons are true:

x = 2
(x < 3) or (x == 3)    # one is true, so returns True
(x < 1) or (x == 3)             # both are false, so returns False

Built-in Classes

Tychos has only a few classes that are used to create the basic simulated objects in the Tychos universe as well as a few tools for analyzing those objects in the simulated world. The graphical objects in Tychos that can be used are the circle, the rectangle, the arrow, the line, the label, the spring and the poly_line.

circle

A circle is drawn as a colored circle in the World View. Circle objects can have borders, labels, or even image overlays (see below).

c = circle()
c_big_red = circle(pos=vec(50, 0), radius=25, color="red")
c_green = circle(pos=vec(100, 0), color="green", opacity=.5)
c_green.border_size=5
c_green.border_color="blue"
c.label_text="hi"
c.label_color="white"
c.label_font="Courier"

Below is the constructor for the circle object that shows its default values:

circle(
   pos=vec(0,0), 
   radius=10, 
   color="black",
   no_fill=False,
   fill=None,
   image="",   
   opacity=1,
   visible=True, 
   motion_map=False,
   label_text="",
   label_color="black"
   label_font="default",
   label_style={},
   border_size=0,
   border_color="black",
   border_style="none"
)
  • pos — The initial position of your circle as a vector with x,y,z coordinates.

  • radius — The radius of the circle.

  • color — The circle will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • no_fill — If set to True, the area inside the circle will be transparent.

  • fill — Optional argument for rendering the circle filled with either a linear_gradient or radial_gradient.

  • image — A URL that identifies a JPEG, GIF, SVG or PNG image.

  • opacity — The circle will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The circle can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

  • label_text - The text of an attached label.

  • label_color - The color of the attached label text.

  • label_font - The font family of the attached label text.

  • label_style - A dictionary whose key-value pairs match CSS font styling attributes of the attached label text.

  • border_size — The border thickness in pixels.

  • border_color — The border will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • border_style — Sets the border as either solid (default = "none") or "dash" for a dashed border, or "dot" for a dotted border.

These attributes may also be modified on the circle after it is created. In particular, one will usually change the pos attribute of a circle in the Calculations editor to show movement. e.g.

# Calculations editor
c.pos = c.pos + vec(1, 0.25)

circle.remove()

circle objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

circle.rotate()

circle objects can be rotated.

circle.rotate(angle=0, axis=vec(0, 0)) — Rotates the circle object by a given angle value in radian units. You can also provide an optional vector that identifies the axis of rotation. This method should only be called from the Calculations code editor.

circle.image

circle objects can also be represented with an image by setting the image attribute of the object. The text must be a URI link to a graphic file that can be a PNG, SVG, GIF, or JPEG image.

rocket = circle(pos=vec(0, 0), radius=10)
rocket.image = "https://upload.wikimedia.org/wikipedia/commons/3/3d/Spacecraft.png"

The above image also demonstrates the use of the direction function as well as the rotate method:

rocket.rotate(direction(rocket.v))

ellipse

An ellipse is drawn as a colored ellipse in the World View.

e1 = ellipse(pos=vec(0, 0), size=vec(10,5), color="green", opacity=.6)
e2 = ellipse(pos=vec(10, 0), size=vec(5,10), color="blue", opacity=.6)
e3 = ellipse(pos=vec(0, -10), size=vec(5,5), color="red", opacity=.6)

Below is the constructor for the ellipse class that shows its default values:

ellipse(
   pos=vec(0,0), 
   size=vec(10,5), 
   color=default_color, 
   no_fill=False,
   fill=None,
   border_size=0,
   border_color=default_color,
   border_style="none",
   image="",   
   opacity=1, 
   visible=True, 
   motion_map=False,
   label_text=""
   label_color=default_color,
   label_font="default",
   label_style={}
) 
  • pos — The initial position of your ellipse as a vector with x,y,z coordinates.

  • size — The size of the ellipse given as a vector with x,y,z coordinates.

  • color — The ellipse will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • no_fill — If set to True, the area inside the ellipse will be transparent.

  • fill — Optional argument for rendering the ellipse filled with either a linear_gradient or radial_gradient.

  • border_size — The border thickness in pixels.

  • border_color — The border will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • border_style — Sets the border as either solid (default = "none") or "dash" for a dashed border, or "dot" for a dotted border.

  • image — A URL that identifies a JPEG, GIF, SVG or PNG image.

  • opacity — The ellipse will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The ellipse can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

  • label_text - The text of an attached label.

  • label_color - The color of the attached label text.

  • label_font - The font family of the attached label text.

  • label_style - A dictionary whose key-value pairs match CSS font styling attributes of the attached label text.

These attributes may also be modified on the ellipse after it is created, just like the circle.

ellipse.remove()

ellipse objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

ellipse.rotate()

ellipse objects can be rotated, just like the circle.

ellipse.rotate(angle=0, axis=vec(0, 0)) — Rotates the ellipse object by a given angle value in radian units. You can also provide an optional vector that identifies the axis of rotation. This method should only be called from the Calculations code editor.

ellipse.image

ellipse objects can also be represented with an image by setting the image attribute of the object. The text must be a URI link to a graphic file that can be a PNG, SVG, GIF, or JPEG image. See the circle above for more detail

rectangle

A rectangle is very similar to a circle but it is represented as a colored rectangle in the World View.

# Initial State editor
r = rectangle(size=vec(20,10))
r_big_red = rectangle(pos=vec(25, 0), size=vec(25, 25), color="red")
r_green = rectangle(pos=vec(50, 0), color="green", opacity=.5)
r_green.border_size=5
r_green.border_color="blue"
r.label_text="hi"
r.label_color="white"
r.label_font="Courier"

Below is the constructor for the rectangle object that shows its default values:

rectangle( 
   pos=vec(0,0), 
   size=vec(10,5), 
   color=default_color,
   no_fill=False,
   fill=None, 
   border_size=0,
   border_color=default_color,
   border_style="none",
   image="",   
   opacity=1, 
   visible=True, 
   motion_map=False,
   label_text="",
   label_color=default_color,
   label_font="default",
   label_style={}
)
  • pos — The initial position of your rectangle as a vector with x,y,z coordinates.

  • size — The size of the rectangle given as a vector with x,y,z coordinates.

  • color — The rectangle will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • no_fill — If set to True, the area inside the rectangle will be transparent.

  • fill — Optional argument for rendering the rectangle filled with either a linear_gradient or radial_gradient.

  • border_size — The border thickness in pixels.

  • border_color — The border will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • border_style — Sets the border as either solid (default = "none") or "dash" for a dashed border, or "dot" for a dotted border.

  • image — A URL that identifies a JPEG, GIF, SVG or PNG image.

  • opacity — The rectangle will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The rectangle can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

  • label_text - The text of an attached label.

  • label_color - The color of the attached label text.

  • label_font - The font family of the attached label text.

  • label_style - A dictionary whose key-value pairs match CSS font styling attributes of the attached label text.

These attributes may also be modified on the rectangle object after it is created. In particular, one will usually change the pos attribute in the Calculations editor to show movement. e.g.

# Calculations editor
r1.pos = r1.pos + vec(1, 0.25)

rectangle.remove()

rectangle objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

rectangle.rotate

You can also rotate a rectangle object in order to simulate rotational behavior.

rectangle.rotate(angle=0, axis=vec(0, 0)) — Rotates the rectangle object by a given angle value in radian units. You can also provide an optional matrix that identifies the center of rotation. This method should only be called from the Calculations code editor.

Example:

# Calculations editor
r1.rotate(-pi/4)
r2.rotate(radians(90))
r3.rotate(radians(45))

rectangle.image

Just as with circle objects, rectangle objects can also be represented with an image by setting the image attribute of the object.

r.image = "https://some.image.url.jpg"

arc

The arc object represents a graphical elliptical arc that sweeps out from a starting angular position to an ending angular position.

# Different arc objects
a1 = arc(pos=vec(10, 10), size=vec(10, 10), start=0, end=pi/2, mode="chord",     color="green", border_color="purple", border_size=3)
a2 = arc(pos=vec(-10, 10), size=vec(10, 5), start=0, end=5*pi/4, mode="open",     color="red", border_color="purple", border_size=3)
a3 = arc(pos=vec(-10, -10), size=vec(10, 10), start=0, end=pi/2, mode="pie",     color="orange", border_color="purple", border_size=3)
a4 = arc(pos=vec(-10, 20), size=vec(10, 10), start=pi, end=6*pi/5, mode="pie",     no_fill=True, border_color="purple", border_size=3)

Below is the constructor for the arc object that shows its default values:

arc(
   pos=vec(0,0), 
   size=vec(10,5), 
   start=0,
   end=pi,
   mode="chord",
   no_fill=False,
   fill=None,
   color=default_color, 
   border_size=0,
   border_color=default_color,
   border_style="none"
   opacity=1, 
   visible=True, 
   motion_map=False,
) 
  • pos — The initial center position of your arc as a vector with x,y,z coordinates.

  • size — The size of the arc ellipse given as a vector with x,y,z coordinates.

  • start — The starting angular value for the arc sweep.

  • end — The ending angular value of the arc sweep.

  • mode — The render mode which can be "chord", "open", or "pie".

  • no_fill — If set to True, the area inside the arc will be transparent.

  • fill — Optional argument for rendering the arc filled with either a linear_gradient or radial_gradient.

  • color — The arc will be filled in this color. Use HTML colors e.g. "#ff3300", "blue".

  • border_size — The border thickness in pixels.

  • border_color — The border will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • border_style — Sets the border as either solid (default = "none") or "dash" for a dashed border, or "dot" for a dotted border.

  • opacity — The arc will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The arc can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

arc.remove()

arc objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

arc.rotate

You can also rotate an arc object in order to simulate rotational behavior.

arc.rotate(angle=0, axis=vec(0, 0)) — Rotates the arc object by a given angle value in radian units. You can also provide an optional vector that identifies the center of rotation. This method should only be called from the Calculations code editor.

arrow

The arrow object represents a graphical arrow and is commonly used to illustrate vectors, but can be used for representing anything in your simulations.

# Initial State editor
c = circle(pos=vec(0,0), color="green")
a = arrow(pos=c.pos, size=vec(20, 20), color="purple")
a.show_components = True

Below is the constructor for the arrow object that shows its default values:

arrow(
   pos=vec(0,0), 
   size=vec(0,1), 
   color=default_color, 
   stroke=0,
   style="none"
   opacity=1,
   show_components=False, 
   visible=True, 
   motion_map=False,
) 
  • pos — The initial position of your arrow tail as a vector with x,y,z coordinates.

  • size — The size of the arrow given as a vector with x,y,z coordinates.

  • color — The arrow will be drawn in this color. Use HTML colors e.g. "#ff3300", "blue".

  • stroke — The arrow thickness in pixels.

  • style — An arrow can have a "dash" style, or a "dot" style, or "none" which is the default.

  • opacity — The arrow will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • show_components — This flag tells Tychos to attach additional x and y component arrows.

  • visible — The arrow can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

arrow.remove()

arrow objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

line

The line class draws a line and is commonly used to illustrate some connecting member like a string or cable, but could really represent anything you like.

myLine = line(pos=vec(0, 0), pos2=vec(20, 20), color="purple", stroke=2)
anotherLine = line(pos=vec(0, 0), pos2=vec(10, 20), color="green", stroke=10)

Below is the constructor for the line class that shows its default values:

line(
   pos=vec(0,0), 
   pos2=vec(1,0), 
   color=default_color,
   stroke=1,
   style="none", 
   opacity=1, 
   visible=True, 
   motion_map=False
)
  • pos — coordinates for the starting point of the line as vector

  • pos2 — coordinates of the termination point of the line as a vector.

  • color — HTML color value for your line, e.g. "red" or "#ff0000".

  • stroke — Stroke value that determines the visual thickness of the line. This is measured in pixels.

  • style — Sets the line as either solid (default = "none") or "dash" for a dashed line, or "dot" for a dotted line.

  • opacity — The line will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The line can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

line.remove()

line objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

poly_line

The poly_line class draws a series of connected lines between a given set of points. This object can be used to represent a complex path or a shape other than a circle or rectangle.

Below is the constructor for the poly_line class that shows its default values:

poly_line(
   pos=vec(0,0), 
   color=default_color,
   stroke=1,
   style="none", 
   fill=False,
   opacity=1, 
   visible=True, 
   motion_map=False
)
  • pos — coordinates for the starting point of the poly_line as a vector.

  • color — HTML color value for your poly_line, e.g. "red" or "#ff0000".

  • stroke — Stroke value that determines the visual thickness of the poly_line. This is measured in pixels.

  • style — Can be "none" for solid segments, "dash" for dashed line segments or "dot" for dotted line segments.

  • fill — Boolean value (True or False) for displaying the poly_line object as a filled in solid with a color, or an optional argument for rendering the inside area with either a linear_gradient or radial_gradient object.

  • opacity — The poly_line will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The poly_line can be hidden from view by setting this flag to false.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

poly_line objects have a number of methods for manipulating the poly_line points, like adding new points, changing existing points, removing points, etc:

  • set_points: (points) -> Set the points for the poly_line given a List of points.

  • translate: (delta_position) -> Move all the points according to a vector.

  • rotate: (angle, axis) -> Transform the points a certain angle measurement about an axis. This axis is relative to the first point in the poly_line.

  • npoints(): -> Returns the number of points in the poly_line.

  • append: (*points) -> Add a point (or many points) to the end of the poly_line.

  • unshift: (*points) -> Add a point (or many points) at the beginning of the poly_line.

  • shift: () -> Remove the first point in the poly_line object.

  • splice: (start, how_many, *points) -> Insert a point or several points anywhere at the specific index position. You can also identify how many points you would like to remove from the poly_line as well.

  • pop: (n) -> Get the vector for point number n and remove it. Can use negative values, where -1 is the last point, -2 the next to the last, etc.

  • clear: () -> Remove all the points in the poly_line.

  • modify: (n, point) -> Modify the point at the specified n position, replacing it with the given vector.

  • slice: (start, end) -> Returns the set of points (but does not remove them) from the poly_line object beginning at the start value and ending at the end index position.

poly_line.remove()

poly_line objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

spring

A spring is a visual representation of a common elastic connector that displays a given number of coils that dynamically change shape once the dimensions of the spring are changed in the Calculations Pane.

The code below shows the three different spring objects above that have different lengths, widths and coil numbers. The circle objects are shown just for reference.

# Initial State editor
c1 = circle(pos=vec(0, 0), radius=2, color="green")
spring1 = spring(pos=vec(0, 20), pos2=c1.pos, color="black", coils=20, width=2)
c2 = circle(pos=vec(10, 0), radius=2, color="green")
spring2 = spring(pos=vec(10, 20), pos2=c2.pos, color="black", coils=10, width=4)
c3 = circle(pos=vec(20, 0), radius=2, color="green")
spring3 = spring(pos=vec(20, 20), pos2=c3.pos, color="black", coils=20, width=2)

Below is the constructor for the spring class that shows its default values:

spring(
   pos=vec(0,0), 
   pos2=vec(1,0), 
   color=default_color,
   coils=5,
   width=10,
   stroke=1, 
   opacity=1, 
   visible=True, 
   motion_map=False
)
  • pos — coordinates for the starting point of the spring as a 2D vector.

  • pos2 — coordinates of the termination point of the spring as 2D vector

  • color — HTML color value for your spring, e.g. "red" or "#ff0000".

  • coils — The number "coil" zig-zags.

  • width — The width of the "coil" zig-zags.

  • stroke — Stroke value that determines the visual thickness of the spring. This is measured in pixels.

  • opacity — The spring will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The spring can be hidden from view by setting this flag to false.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

These attributes may also be modified after the spring is created.

spring.remove()

spring objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

label

You can add text labels to any scenario using the label object.

lbl_dog = label(pos=vec(0,0), size=vec(20,20), text="dog", color="green")
lbl_cat = label(pos=vec(0,-15), size=vec(10,10), text="cat", color="red")
lbl_mouse = label(pos=vec(0,15), size=vec(10,10), text="mouse", color="blue")
lbl_dog.font="Impact"
lbl_cat.font="Times"
lbl_mouse.font="monospace"
lbl_dog.style = {"text-shadow":"3px 3px 3px black"}
lbl_cat.style = {"font-style":"oblique"}
lbl_mouse.style = {"text-decoration":"underline"}// Some code

Below is the constructor for the label class that shows its default values:

label(
   pos=vec(0,0), 
   size=vec(10,10), 
   text="",
   color=default_color, 
   font="default",
   style={},
   opacity=1, 
   visible=True, 
   motion_map=False
)
  • pos — coordinates for the center point of the label as a 2D vector.

  • size — The width and height of the label as a 2D vector.

  • text — The text of the label as a string.

  • color — HTML color value for your label, e.g. "red" or "#ff0000".

  • font — CSS font family identifier, e.g. "Times", or "Courier"

  • style — A dictionary with key value pairs that represent CSS font styling rules.

  • opacity — The label will be drawn with an opacity between 1 and 0, representing 100% opaque to 100% transparent.

  • visible — The label can be hidden from view by setting this flag to False.

  • motion_map — This flag tells Tychos to attach a series of strobe images called a motion map.

These attributes may also be modified after the label object is created.

label.remove()

label objects, like all Tychos objects can be removed from the scenario world scope. Once this done, you will not be able to reference the object as it will be removed from your scenario's collection of viewable objects.

label.rotate(angle=0)

You can rotate a label as shown below:

label3.rotate(pi/4)

World

The world object represents the viewable area of the scenario.

world.set_extents

You can set the viewable extents of the world in the Settings Pane, or by calling the following method on the world object:

world.set_extents(pos=vec(0,0), size=vec(10,10))

The inputs are two vector objects representing the center position of the view of the world, and secondly the size of the viewable world.

Gradient Fills

The radial_gradient and linear_gradient objects are used as fill parameters for the following objects:

  • circle

  • rectangle

  • ellipse

  • arc

  • poly_line

radial_gradient

Below is the constructor for the radial_gradient object that shows its default values:

radial_gradient( start_x=50, start_y=50, end_x=50, end_y=50, colors=[] offsets=[] )

  • start_x — This attribute defines the relative x position (as a percentage) of the start the radial gradient.

  • start_y — This attribute defines the relative y position (as a percentage) of the start the radial gradient.

  • end_x — This attribute defines the relative x position (as a percentage) of the end the radial gradient.

  • end_y — This attribute defines the relative y position (as a percentage) of the end the radial gradient.

  • colors — A list of HTML color values for your radial_gradient, e.g. "red" or "#ff0000".

  • offsets — A list of corresponding numerical values defining where the associated gradient stop is placed along the gradient.

Example:

c1 = circle(pos=vec(-50,0), radius=10)
c1.fill = radial_gradient(start_x=10, start_y=10, end_x=30, end_y=30, colors=["white", "red", "black"], offsets=[0,50,100])
r1 = rectangle(size=vec(20,20), pos=vec(0,50))
r1.fill = radial_gradient(start_x=10, start_y=10, end_x=30, end_y=30, colors=["white", "purple", "black"], offsets=[0,40,100])
e1 = ellipse(pos=vec(50,50), size=vec(20, 10))
e1.fill = radial_gradient(start_x=10, start_y=10, end_x=30, end_y=30, colors=["white", "purple", "black"], offsets=[0,40,100])
a1 = arc(pos=vec(-50, 50))
a1.fill = radial_gradient(start_x=10, start_y=10, end_x=30, end_y=30, colors=["white", "purple", "black"], offsets=[0,40,100])
p1 = poly_line(pos=vec(0, 0), stroke=1, color="red")
p1.append(vec(0,0))
p1.append(vec(25,0))
p1.append(vec(0,25))
p1.append(vec(0,0))
p1.fill = linear_gradient(colors=["black", "red"])
c2 = circle(pos=vec(50,0), radius=10)
c2.fill = linear_gradient(colors=["black", "red"])
r2 = rectangle(size=vec(20, 20), pos=vec(0,-50))
r2.fill =linear_gradient(colors=["yellow", "red"])
e2 = ellipse(pos=vec(50,-50), size=vec(20, 10))
e2.fill = linear_gradient(colors=["orange", "red", "black"], offsets=[0,30,100])
a2 = arc(pos=vec(-50, -50))
a2.fill = linear_gradient(colors=["red", "black"], offsets=[30, 100], angle=pi/2)

linear_gradient

Below is the constructor for the linear_gradient object that shows its default values:

linear_gradient( angle=0, colors=[] offsets=[] )

  • angle — This attribute transforms the linear gradient by rotating the gradient from the relative center position of the filled object. The value is defined in radians.

  • colors — A list of HTML color values for your radial_gradient, e.g. "red" or "#ff0000".

  • offsets — A list of corresponding numerical values defining where the associated gradient stop is placed along the gradient.

Interface Widgets

Tychos also provides several "widgets" for displaying data in different ways as well as adding user interactivity so that your simulations can respond to input.

graph

A graph is a 2-dimensional chart of data that you specify in the Initial State editor. Each graph that is created will appear by default on the right side of the World View, but can be aligned to the left instead. Your program needs to add points to the graph with the plotcommand.

g1 = graph(title="Line Graph", align="left", width="50%", height=200)
g1.plot(color="purple", mode="line", x=[0,1,2,3], y=[0, 10, 10, 0], fill=True)
g1.plot(color="green", mode="line", x=[0,1,2,3], y=[0, 2, 4, 9], fill=False)
g2 = graph(title="Scatter Graph", align="right", width="50%", height=400)
x_vals = random.sample(range(-50, 50), 100)
y_vals = random.sample(range(0, 100), 100) 
g2.plot(color="orange", mode="scatter", x=x_vals, y=y_vals)

Here is the constructor for creating a graph object

graph(
    title="Graph", 
    align="right", 
    y_axis="Y", 
    x_axis="X",
    width=500,
    height=350,
    plot_rate=None
)
  • title = Optional text that will appear at the top of the graph.

  • align = Optional value of "left" or "right" to align the graph to the corresponding side of the view window.

  • y_axis = Optional text that will appear on the left side of the graph as the vertical axis label.

  • x_axis = Optional text that will appear at the bottom of the graph as the horizontal axis label.

  • width = Optional numeric value in pixels for setting the width, or a text value percentage e.g. "50%" or "90%".

  • height = Optional numeric value in pixels for setting the height, or a text value percentage e.g. "50%" or "90%".

  • plot_rate = Optional numerical value greater than 0 that sets the individual graph's plotting schedule. This over rides the default Graph Strobe Rate value set in the Settings tab.

Plotting Values

To plot values for the graph, the plot method is used. You can either plot points by calling the plot method with the x and y arguments set to single numerical inputs, or to plot more than a single point, you can instead set the x and y arguments to be lists of numerical values.

When plotting, Tychos will plot the points you specify when the simulation plot timer has expired. This is called "strobing" the graph. There is a default plot timer set in the Settings tab called Graph Strobe Rate for the scenario, but this can be over ridden by setting the graph's plot rate.

Note that depending on the simulation step time and the graph plot rate, graph plots may not appear on the graph at the exact time specified by the graph plot rate. For example, if the plot rate is actually faster than the animation step rate, the plotting of the points will not appear to be in sync because the animation is actually running slower than rate at which points should be plotted.

The arguments for the plot method are shown below:

graph.plot(
    x=0, 
    y=0, 
    color=default_color,
    mode="line",
    fill=False
)
  • x = This is either a single numerical value or a list of numerical values.

  • y = This is either a single numerical value or a list of numerical values.

  • color = Optional "line" or "scatter" that will either display the points as connected with lines, or not. The default is to connect the plotted points with lines.

  • mode = Optional "line" or "scatter" that will either display the points as connected with lines, or not. The default is to connect the plotted points with lines.

  • fill = Optional boolean value for filling in the plotted area.

Clearing Values

To clear values for the graph, the clear method is used. Clearing the plotted values occurs immediately when the method is called, clearing all the plotted values from the graph:

graph.clear()

bar_chart

A bar_chart is a chart of data that is displayed as a set of bars representing an array of data values. Each bar_chart that is created will appear on the right side of the World View.

bc_energy = bar_chart(title="Energy Bar Chart", min=0, max=500)
bc_energy.data = [150, 250, 200, 500]
bc_energy.colors = ["red", "blue", "green", "black"]
bc_energy.labels = ["KE", "Ue", "Ug", "TE"]
  • title = Optional text that will appear at the top of the bar_chart.

  • align = Optional value of "left" or "right" to align the bar chart to the corresponding side of the view window.

  • min = Optional minimum value whose default is 0. If any bar data value is less than this minimum, the bar will be truncated.

  • max = Optional maximum value whose default is 1. This sets the maximum viewable bar height. If any bar data value is greater than this maximum, the bar will be truncated.

  • width = Optional numeric value in pixels for setting the width, or a text value percentage e.g. "50%" or "90%".

  • height = Optional numeric value in pixels for setting the height, or a text value percentage e.g. "50%" or "90%".

bar_chart.data

bar_chart.data — Sets the data values for the bars in the bar chart.

# Set the data for the bars
bc_energy.data =[x,y,z,w] # Where x, y, z, and w are numerical data values

bar_chart.labels

bar_chart.labels — Defines a set of labels - one label corresponding to each data bar in the chart. If the number of labels does not match the number of bars set by the number of data values, then a numbered label will be assigned to the extra data value.

# Set the labels for the bars
bc_energy.labels = ["KE", "Ue", "Ug", "TE"]

bar_chart.colors

bar_chart.colors — List of colors, one color corresponding to each data bar in the chart. If the number of colors does not match the number of bars set by the number of data values, then any extra bars will be given the default HTML color of #aaa.

# Set the colors for the bars
bc_energy.colors = ["red", "blue", "green", "black"]

pie_chart

A pie_chart is a chart of data that is displayed as circle that is "sliced" into different pieces of a "pie" representing the relative proportion to the sum of all the values in the chart's data. Each pie_chart that is created will appear on the right side of the World View by default, but can be aligned to the left.

pc = pie_chart(title="Pie Chart", data=[10,20, 30], width=300, height=200)
pc.labels = ["yes", "no", "maybe"]
pc.colors = ["lightgreen", "red", "gold"]

The constructor options for adding a pie_chart to your scenario are the following:

  • title = Optional text that will appear at the top of the pie_chart.

  • align = Optional value of "left" or "right" to align the pie_chart to the corresponding side of the view window.

  • width = Optional numeric value in pixels for setting the width, or a text value percentage e.g. "50%" or "90%".

  • height = Optional numeric value in pixels for setting the height, or a text value percentage e.g. "50%" or "90%".

pie_chart.data

pie_chart.data — Sets the data values for the pie slices in the pie chart.

# Set the data for the bars
pc.data =[x,y,z] # Where x, y, z, are numerical data values

pie_chart.labels

pie_chart.labels — Defines a set of labels - one label corresponding to each data slice in the chart. If the number of labels does not match the number of data values, then a numbered label will be assigned to the extra data value.

# Set the labels for the pie chart slices
pc.labels = ["yes", "no", "maybe"]

pie_chart.colors

pie_chart.colors — List of colors, one color corresponding to data value in the chart. If the number of colors does not match the number of data values, then any extra values will be given the default colors.

# Set the colors for the data values
pc.colors = ["lightgreen", "red", "gold"]

table

A table displays data organized in columns and rows.

Each table that is created will appear on the right side of the World View. When creating a table you can give it a title, and will need to define the column names for the table. You can also optionally define the precision for the numerical values being displayed in the table.

Below is the constructor for the table widget and default values:

table(title="Table", align="right", columns=[], precision=4)

  • title = Optional text that will appear at the top of the table widget.

  • align = Optional value of "left" or "right" to align the table to the corresponding side of the view window.

  • columns — A list of strings representing the column names that will appear in the table.

  • precision — Optional precision level for representing numerical values.

table.add_row([value1, value2, ...])

table.add_row([values]) — This adds a row of data to the table. Keep in mind that you must supply a list of values whose length is equal to that of the columns in the table.

  • values = A list of values corresponding to the columns in the table.

Example:

# Initial State editor
table1 = table(title="example")

table1.columns = ["Time", "X Pos", "Y Pos"]

table1.precision = 6
# Calculations editor
# c is a circle object that is moving
table1.add_row([t, c.pos.x, c.pos.y])

meter

A meter is a numeric display of data. Each meter that is created will appear on the left side of the World View. Your program needs to tell the meter what value it needs to display by using the display command.

Below is the constructor for the meter widget and default values:

meter(title="Meter", align="left", color="black", suffix="")

  • title = Optional text that will appear at the top of the meter widget.

  • align = Optional value of "left" or "right" to align the meter to the corresponding side of the view window.

  • color — HTML color value for your meter, e.g. "red" or "#ff0000".

  • suffix — text added at the end of the data value display.

meter.display()

meter.display(value) — Displays the value on the meter.

  • value = Numeric value to be displayed.

Example:

# Initial State editor
mt = meter(title="Time", color="red", suffix="s")
# Calculations editor
mt.display(t)

gauge

A gauge is an analog display of data that is very similar to a meter that you specify in the Initial Sate pane. Each gauge that is created will appear on the left side of the World View. Gauges also need to to be set up with a specific minimum and maximum value for identifying the range of the gauge. Your scenario needs to tell the gauge what value it needs to display by using the display command.

Below is the constructor for the Gauge widget and default values:

gauge(title="Gauge", align="left", min=0, max=100, color="black")

  • title = Optional text that will appear at the top of the gauge widget.

  • align = Optional value of "left" or "right" to align the gauge to the corresponding side of the view window.

  • min = The minimum value of the gauge

  • max = The maximum value of the gauge

  • color — HTML color value for your gauge, e.g. "red" or "#ff0000".

gauge.display()

gauge.display(value) — Displays the value in the Gauge.

Example:

# Initial State editor