VPython Object - Revision history

Adharayan3: Changes add missing beginner-friendly explanations of modern VPython syntax, pos versus axis, arrow scaling, animation loops, custom object attributes, vector operations, and how arrows are used to visually represent physics quantities like force, velocity, electric fields, and magnetic fields.

2026-04-26T21:44:29Z

Changes add missing beginner-friendly explanations of modern VPython syntax, pos versus axis, arrow scaling, animation loops, custom object attributes, vector operations, and how arrows are used to visually represent physics quantities like force, velocity, electric fields, and magnetic fields.

← Older revision		Revision as of 17:44, 26 April 2026
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	Objects in VPython are intended to represent data in ways that can be easily visualized and understood by both the user and the computer. Each object has a type it belongs to, which determines its default attributes, as well as how the computer will choose to display it when the program runs. Objects must be uniquely named if you wish to refer to them again later in your program, and any graphical object you create (spheres, boxes, curves, arrows, etc.) continue to exist for as long as your program remains running - VPython will continue to display them regardless of where they are positioned. If you change an attribute of an object, such as its position or color, VPython will automatically display the object in its new location and/or with its new color.		Objects in VPython are intended to represent data in ways that can be easily visualized and understood by both the user and the computer. Each object has a type it belongs to, which determines its default attributes, as well as how the computer will choose to display it when the program runs. Objects must be uniquely named if you wish to refer to them again later in your program, and any graphical object you create (spheres, boxes, curves, arrows, etc.) continue to exist for as long as your program remains running - VPython will continue to display them regardless of where they are positioned. If you change an attribute of an object, such as its position or color, VPython will automatically display the object in its new location and/or with its new color.

			Another useful feature of VPython objects is that programmers can create their own attributes in addition to the built-in visual attributes. For example, a sphere already has attributes such as pos, radius, and color, but a programmer can also add attributes such as mass, charge, velocity, or momentum. This is especially useful in physics because the same object can store both its visual information and its physical information. A sphere representing a charged particle might have particle.q = 1e-9, while a moving object might have ball.p = ball.mass*ball.v. These custom attributes do not automatically change how the object looks, but they make the code easier to organize because the physical properties are attached directly to the object they describe.

	For example, let's say you create a sphere called 'ball' - by default, ball has attributes pre-assigned to it, such as ball.pos (the .pos attribute signifies the position of the sphere) or ball.color (the .color attribute allows you to change the color of the sphere). Also, in addition to the preset attributes, you can also create new ones. Besides the position and radius, you can also create attributes for mass (ball.mass), velocity (ball.vel), momentum (ball.momentum), or anything else you see fit. Of course, not all attributes need to be added manually. They can be left blank and filled in with a default value which the program automatically assigns them		For example, let's say you create a sphere called 'ball' - by default, ball has attributes pre-assigned to it, such as ball.pos (the .pos attribute signifies the position of the sphere) or ball.color (the .color attribute allows you to change the color of the sphere). Also, in addition to the preset attributes, you can also create new ones. Besides the position and radius, you can also create attributes for mass (ball.mass), velocity (ball.vel), momentum (ball.momentum), or anything else you see fit. Of course, not all attributes need to be added manually. They can be left blank and filled in with a default value which the program automatically assigns them

	==Basics==		==Basics==

			One important note is that VPython syntax can look different depending on whether you are using older desktop VPython, newer installed VPython, or browser-based GlowScript/Web VPython. Older examples may use

			from visual import *

			, while many newer Python examples use

			from vpython import *.

			In GlowScript/Web VPython, some import statements may not be necessary because the browser environment already provides the VPython objects and functions. Because of this, students should focus less on memorizing one exact import style and more on understanding the structure of object creation: choosing an object type, giving it attributes, and then updating those attributes later if needed. The current VPython documentation describes VPython as a tool for creating navigable real-time 3D animations and supporting 3D vector operations, which is why it is useful for physics modeling.

	To make an object and visualize it, it is required to import functions by writing following lines on the top of the code. If you are using Glowscript, these imports are not required.		To make an object and visualize it, it is required to import functions by writing following lines on the top of the code. If you are using Glowscript, these imports are not required.

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	==Attributes==		==Attributes==
	Many objects in VPython carry common attributes regardless of their type. This section will cover the attributes you will be utilizing the most in this class.		Many objects in VPython carry common attributes regardless of their type. This section will cover the attributes you will be utilizing the most in this class.

			Vectors are one of the most important parts of VPython because most physics quantities have both magnitude and direction. A vector in VPython can be written using vec(x,y,z) or vector(x,y,z), and it stores three components: x, y, and z. These vectors can be added, subtracted, multiplied by scalars, and used in functions such as mag(), norm(), dot(), and cross(). This is important because many physics calculations begin by finding a relative position vector, such as r = obsloc - charge.pos. From there, the magnitude can be found with mag(r), and the unit vector can be found with norm(r). The VPython documentation states that vector objects have the properties of 3D vectors in math and science, and it lists common vector operations such as magnitude, unit vectors, dot products, and cross products.

	===Position===		===Position===
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	ball = objectType(pos(4,2,0))		ball = objectType(pos(4,2,0))

			A common source of confusion is that the pos attribute does not mean the exact same thing for every object. For a sphere, pos represents the center of the sphere, so sphere(pos=vec(0,0,0)) places the center of the sphere at the origin. For an arrow, however, pos represents the tail or starting point of the arrow, not its center. This matters a lot in physics simulations because a sphere may represent a particle located at a point, while an arrow may represent a vector quantity starting from a specific observation location. For example, if an electric field is measured at obsloc, the arrow should usually have pos=obsloc, because the arrow is drawn starting from the location where the field is being shown. The official VPython documentation lists a sphere’s pos as the position of its center, while an arrow’s pos is listed as the position of its tail.

	===Color===		===Color===
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	The axis attribute also determines orientation of other objects, such as rings or cylinders, but arrows are the only object whose size is specifically tied to the axis attribute.		The axis attribute also determines orientation of other objects, such as rings or cylinders, but arrows are the only object whose size is specifically tied to the axis attribute.

			The axis attribute is especially important because it often controls both direction and length. For an arrow, axis is the vector from the tail of the arrow to the tip of the arrow, so changing the axis changes where the arrow points and how long it appears. For example, arrow(pos=vec(0,0,0), axis=vec(3,0,0)) creates an arrow that begins at the origin and points three units in the positive x-direction. This is useful in physics because vectors such as force, velocity, acceleration, momentum, electric field, and magnetic field all have both magnitude and direction. In VPython, the direction of the arrow comes from the direction of the axis vector, while the size of the arrow comes from the magnitude of that axis vector. The VPython documentation describes the arrow axis as extending from the tail to the tip.

			In physics simulations, arrows often need to be scaled before they are displayed. Real physical values may be too large or too small to draw directly on the screen. For example, an electric field might have a magnitude of thousands of newtons per coulomb, while the object positions in the simulation may only be a few meters apart. If the field vector is used directly as an arrow axis, the arrow may become so large that it leaves the screen, or so small that it is impossible to see. To fix this, programmers usually multiply the physical vector by a scale factor, such as arrow(pos=obsloc, axis=Efield*scale). The scale factor does not change the actual physics calculation; it only changes how the vector is visually represented. This is why it is important to separate the real calculated value from the displayed arrow size.

	===Setting Attributes in a Loop===		===Setting Attributes in a Loop===
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	This would create 12 green spheres of radius .5 in a circle 2 units from the origin:		This would create 12 green spheres of radius .5 in a circle 2 units from the origin:
	[[File:12circles.png\|right]]		[[File:12circles.png\|right]]

			Loops are also used to animate objects over time by repeatedly updating their attributes. In a physics model, the position of an object may be updated again and again using its velocity, acceleration, force, or momentum. For example, if a ball has a velocity ball.v, its position can be updated with ball.pos = ball.pos + ball.v*dt, where dt is a small time step. VPython animations should include the rate() function inside the loop because it gives VPython time to redraw the scene and prevents the program from running too quickly to see. Without rate(), the calculations may happen, but the animation may not visibly update on the screen. The VPython documentation describes rate() as an essential part of animation loops because it controls loop speed, allows the display to redraw, and helps mouse and keyboard events work properly.

	===Material/Texture===		===Material/Texture===
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	http://vpython.org/contents/docs/materials.html		http://vpython.org/contents/docs/materials.html

			https://www.glowscript.org/docs/VPythonDocs/index.html

	http://guigui.developpez.com/cours/python/vpython/en/?page=object		http://guigui.developpez.com/cours/python/vpython/en/?page=object

Adharayan3: claiming page

2026-04-26T16:17:34Z

claiming page

← Older revision		Revision as of 12:17, 26 April 2026
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			Claimed by Aarush Dharayan
			Spring 2026

	A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.		A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.

Ewang328 at 01:16, 19 April 2021

2021-04-19T01:16:46Z

← Older revision		Revision as of 21:16, 18 April 2021
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	~~'''Eddy Wang - Spring 2021'''~~

	A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.		A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.

Ewang328 at 01:14, 19 April 2021

2021-04-19T01:14:11Z

← Older revision		Revision as of 21:14, 18 April 2021
Line 1:		Line 1:
			'''Eddy Wang - Spring 2021'''

	A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.		A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.

Mmorris83 at 06:52, 22 October 2019

2019-10-22T06:52:49Z

← Older revision		Revision as of 02:52, 22 October 2019
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	*Claimed by aabid8 (F2018)

	A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.		A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.

Aabid8 at 00:56, 10 October 2018

2018-10-10T00:56:13Z

← Older revision		Revision as of 20:56, 9 October 2018
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	*Claimed by Ddebord3 (2015)
	*Edited by Vnistala3 (2017)
	*Edited by jlee3414 (2018)
	*Claimed by aabid8 (F2018)		*Claimed by aabid8 (F2018)

Aabid8 at 18:33, 27 September 2018

2018-09-27T18:33:32Z

@@ Line 76: / Line 76: @@
 The axis attribute also determines orientation of other objects, such as rings or cylinders, but arrows are the only object whose size is specifically tied to the axis attribute.
 ===Material/Texture===
@@ Line 252: / Line 265: @@
   nameArrow = arrow(pos=(4,2,0), axis=(-2,2,-4), color=color.white)
 ===Box===

Aabid8 at 18:26, 27 September 2018

2018-09-27T18:26:48Z

← Older revision		Revision as of 14:26, 27 September 2018
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	*Edited by Vnistala3 (2017)		*Edited by Vnistala3 (2017)
	*Edited by jlee3414 (2018)		*Edited by jlee3414 (2018)
			*Claimed by aabid8 (F2018)

	A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.		A VPython Object is a representation of data in a specific in VPython both visually and numerically. Each object represents data through its attributes, specific characteristics assigned to each individual object. Objects play an essential role in the necessary knowledge for the coding portion of PHYS 2211 and 2212, as most of your programs will require the extensive usage and manipulation of objects. This page is intended to provide you a background on these objects, especially if you have no prior knowledge of coding or VPython.

			In this class, you should know how to create sphere objects and set their positions, and how to use arrows to show forces, fields, velocities, etc.

	==The Main Idea==		==The Main Idea==
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	==Basics==		==Basics==
	To make an object and visualize it, it is required to import functions by writing following lines on the top of the code.		To make an object and visualize it, it is required to import functions by writing following lines on the top of the code. If you are using Glowscript, these imports are not required.

	from __future__ import division		from __future__ import division
	from visual import *		from visual import *

	Then by writing following line on your code, you can instantiate		Then, by writing following line on your code, you can instantiate

	[variable name] = [object type]([attribute1].[attribute1 type], ... ,[attribute n].[attribute n type])		[variable name] = [object type]([attribute1].[attribute1 type], ... ,[attribute n].[attribute n type])

	~~And you~~ can change attributes of the certain objects		For an object of type sphere, attributes might include position (pos), color, and size. You can also add attributes such as charge or material.
			For an arrow, typical attributes are position (pos), the axis vector, and color.

			You can also change attributes of the certain objects after they have been created.

	[variable name].[attribute] = [new attribute type]		[variable name].[attribute] = [new attribute type]
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	This would return the position of the ball in vector form, or allow you to refer to said position in calculations.		This would return the position of the ball in vector form, or allow you to refer to said position in calculations.

	In addition, the position attribute has three components of its own, which can be accessed by typing		In addition, because this is a vector, the position attribute has three components of its own, which can be accessed by typing:

	ball.pos.x		ball.pos.x
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	===Axis===		===Axis===
	The axis attribute is important specifically for arrows, as it determines the direction which the arrow points and how long it is. For instance, if you wanted to create an arrow parallel to the x-axis with a length of 5, the syntax ~~would~~ be		The axis attribute is important specifically for arrows, as it determines the direction which the arrow points and how long it is. For instance, if you wanted to create an arrow parallel to the x-axis with a length of 5, the syntax could be:

	~~axis~~ = (5,0,0)		myArrow = arrow(pos=vec(5, 0, 0), axis=vec(1, 1, 1), color=color.green)

	meaning the arrow points 5 units along the x axis and is perpendicular to the y and z axes.		meaning the arrow points 5 units along the x axis and is perpendicular to the y and z axes. You will often use arrows to represent forces and fields, where the position will be the observation point, and the axis will the vector value of the force/field/etc.

	The axis attribute also determines orientation of other objects, such as rings or cylinders, but arrows are the only object whose size is specifically tied to the axis attribute.		The axis attribute also determines orientation of other objects, such as rings or cylinders, but arrows are the only object whose size is specifically tied to the axis attribute.
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	nameArrow = arrow(pos=(4,2,0), axis=(-2,2,-4), color=color.white)		nameArrow = arrow(pos=(4,2,0), axis=(-2,2,-4), color=color.white)

			===Setting Attributes in a Loop===
			Sometimes, the position vector will be given, and will be easy to set. In other cases, you may want to create, say 12 spheres in a circle, all a distance 2 from the origin. A quick way to do this is by by using a [http://physicsbook.gatech.edu/VPython_Loops loop] or a [http://physicsbook.gatech.edu/VPython_Lists list].

			For example:

			i = 0
			while i < 2*pi:
			sphere(pos=vec(2cos(i), 2sin(i), 0), radius=0.5, color=color.green)
			i = i + 2*pi/12

			This would create 12 green spheres of radius .5 in a circle 2 units from the origin:

	===Box===		===Box===

Jaeleeps: /* Difficult */

2018-04-19T02:08:04Z

Difficult

@@ Line 341: / Line 341: @@
 [https://trinket.io/glowscript/6ddb3d237e]
-{{hidden
+ # CONSTANTS
-|Title VPython code
+ G = 6.7e-11
-|Body text line 1<br/>Body text line 2
+ mEarth = 6e24
-|headerstyle=background:#ccccff
+ mcraft = 15000
-|style=text-align:center;
+ deltat = 60
-}}
+ t = 0
 ==Connectedness ==

Jaeleeps: /* Difficult */

2018-04-19T02:05:18Z

Difficult

← Older revision		Revision as of 22:05, 18 April 2018
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	'''Applying Texture'''		'''Applying Texture'''
	[[File:EarthandMoon.~~JPG~~]]
			[[File:EarthandMoon.GIF]]

	Trinket Link		Trinket Link
	[https://trinket.io/glowscript/6ddb3d237e]		[https://trinket.io/glowscript/6ddb3d237e]

	VPython
			{{hidden
			\|Title VPython code
			\|Body text line 1<br/>Body text line 2
			\|headerstyle=background:#ccccff
			\|style=text-align:center;
			}}

	==Connectedness ==		==Connectedness ==