VPython Reference

Created by Shuyang Chen

VPython reference page for drawing functions and constants. This page compiles common usages into one page for quick reference. This page assumes that the student knows the basics of creating the objects and just needs a reference page for them.

For detailed and more descriptive pages about objects and how to use them, see VPython 3D Objects and VPython Objects

VPython Template

from __future__ import division
from visual import *

## Constants

## Initialization

## Loop
t = 0
deltat = 1e-10
end = 10

while t < end:
    rate(1000)
    ## Loop Code
    
    t += deltat

VPython Animation and Drawing Reference

Sphere

Source

Example

ball = sphere(pos=(1,2,3), radius=0.4, color=color.blue)

Parameters

Parameter	Type	Description
pos	vector	Position of the object
color	color	Color of the object
radius	number	Radius of the sphere
opacity	number	Opacity of the object
make_trail	boolean	Whether or not to leave behind a trail

Box

Source

Example

cube = box(pos=(1,2,3), length=4, height=5, width=6, color=color.green)

Parameters

Parameter	Type	Description
pos	vector	Position of the object
color	color	Color of the object
length	number	Length of the box
height	number	Height of the box
width	number	Width of the box
axis	vector	Direction the box is facing (facing side is height x width)
opacity	number	Opacity of the object
make_trail	boolean	Whether or not to leave behind a trail

Arrow

Source

Example

arr = arrow(pos=(1,2,3), axis=(4,5,6), color=color.red)

Parameters

Parameter	Type	Description
pos	vector	Position of the object
axis	vector	Direction the arrow is pointing at
color	color	Color of the object
opacity	number	Opacity of the object
shaftwidth	number	Width of the shaft (default: 0.1*(length of arrow))
headwidth	number	Width of the head (default: 2*shaftwidth)
headlength	number	Length of the head (default: 3*shaftwidth)
make_trail	boolean	Whether or not to leave behind a trail

Curve

Source

Example

trail = curve(color=color.orange)
trail.append(pos=(1,2,3))
trail.append(pos=(4,5,6))

Parameters

Parameter	Type	Description
pos	vector array	Positions of the trail
color	color	Color of the object

Label

Source

Example

lbl = label(pos=(1,2,3), text='Information', color=color.cyan)

Parameters

Parameter	Type	Description
pos	vector	Position of the label in the world
xoffset	number	The x component of the line (offset from the pos)
yoffset	number	The y component of the line (offset from the pos)
color	color	Color of the text
text	string	The text to be displayed (line breaks are \n)
font	string	Name of the font to be used
height	number	Height of the font in pixels (default: 13 pixels)
background	color	Color of the background
opacity	number	Opacity of the background of the box
border	number	Distance in pixels from the text to the text box (default: 5 pixels)
box	boolean	Whether or not to draw the box (default: true)
line	boolean	Whether or not to draw the box to the position (default: true)
linecolor	color	Color of the line and box
space	number	Radius in pixels of a sphere around pos where the line is not shown

Color

Source

Example

c = color.red

Basic Colors

Name	Vector	Color
Red	(1,0,0)	color.red
Yellow	(1,1,0)	color.yellow
Green	(0,1,0)	color.green
Orange	(1,0.5,0)	color.orange
Blue	(0,0,1)	color.blue
Cyan	(0,1,1)	color.cyan
Magenta	(1,0,1)	color.magenta
White	(1,1,1)	color.white
Black	(0,0,0)	color.black

VPython Common Constants

Constants

Constant	Common Variable Name	Approximate Value	Code
Speed of light	c	299792458.0	c = 299792458.0
Gravitational Constant	G	6.67408e-11	G = 6.67408e-11
Electron Mass	m_e	9.10938356e-31	m_e = 9.10938356e-31
Proton Mass	m_p	1.6726219e-27	m_p = 1.6726219e-27
Neutron Mass	m_n	1.674927471e-27	m_n = 1.674927471e-27
Electric Constant	oofpez	8.9875517873681764e9	oofpez = 8.9875517873681764e9
Permitivity of Free Space	e0	8.854187817e-12	e0 = 8.854187817e-12
Magnetic Constant	km	1e-7	km = 1e-7
Vacuum Permeability	mu_0	1.2566370614e-6	mu_0 = 1.2566370614e-6
Proton Charge	e	1.602176565e-19	e = 1.602176565e-19
Electron Volt	eV	1.602176565e-19	eV = 1.602176565e-19
Avogadro's Number	N_A	6.0221409e23	N_A = 6.0221409e23
Proton Radius	R_p	0.8775e-15	R_p = 0.8775e-15
E to ionize air	E_ionize	3e6	E_ionize = 3e6
Earth's Magnetic Field	B_Earth	2e-5	B_Earth = 2e-5

Connectedness

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See also

VPython 3D Objects

VPython Objects

VPython Animation

References

VPython Docs

Wikipedia Page on Physical Constants