Arrow with VPython
VPython (Visual Python) is a 3D graphics library that allows us to create and visualize three-dimensional objects on the screen. It is primarily used to visualize the impact of physics equations on the objects' motion.
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Arrow object
The arrow object in VPython is used to represent a vector as an arrow in a 3D space. It has a shaft and head.
Syntax
The arrow object is created using the following syntax:
arrow(pos=vector(x, y, z),axis=vector(dx, dy, dz),opacity=A,length=B,shaftwidth=C,headlength=D,headwidth=E,color=Color)
posis a vector that defines the position of the arrow in three-dimensional space.axisis also a vector, but it defines the direction in which the arrow will be pointing.opacitydetermines how visible the arrow should be.Ais a floating point value ranging fromto where corresponds to the most transparent object and corresponds to an opaque object. lengthdetermines the overall length of the arrow object.Bcan be any positive value.shaftwidthsets the width of the arrow's body.Ccan be any positive value.headlengthdefines the length of the arrowhead.Dcan be any positive integer value.headwidthsets the width of the arrowhead.Ecan be any positive value.colorsets the color of the arrow object. The value of thecolorparameter can be any RGB vector(r, g, b)or a pre-defined color value such ascolor.redorcolor.orange, etc.
Code execution
To execute the provided example code, we must follow the following steps:
Example code
The example code for the arrow object is as follows:
from vpython import *
arrow(pos = vector(0, 0, 0),
opacity = 1,
length = 3,
color = color.yellow)
arrow(pos = vector(4, 0, 0),
axis = vector(1,1,1),
opacity = 0.3,
length = 3,
color = color.orange)
arrow(pos = vector(0, 2, 0),
opacity = 1,
length = 6,
color = color.red)
arrow(pos = vector(0, 5, 0),
opacity = 1,
length = 3,
shaftwidth = 4,
color = color.blue)
arrow(pos = vector(0, -3, 0),
opacity = 1,
length = 3,
headwidth = 4,
color = color.cyan)
arrow(pos = vector(0, -6, 0),
opacity = 1,
length = 3,
headlength = 4,
color = color.magenta)
# Create X-axis arrow
arrow_x = arrow(pos=vector(0, 0, 0), axis=vector(1, 0, 0), color=color.red, shaftwidth=0.05, length = 10)
# Create Y-axis arrow
arrow_y = arrow(pos=vector(0, 0, 0), axis=vector(0, 1, 0), color=color.green, shaftwidth=0.05, length = 10)
# Create Z-axis arrow
arrow_z = arrow(pos=vector(0, 0, 0), axis=vector(0, 0, 1), color=color.blue, shaftwidth=0.05, length = 10)Code explanation
Line 1: Importing the VPython library.
Lines 3–6: We declared this arrow object as a reference so that you could distinguish how other parameters work.
Lines 8–12: This orange-colored arrow has less opacity and will appear transparent. Moreover, it has the
axisvector of(1, 1, 1), which means it will be pointing in the direction of it.Lines 15–18: This red-colored arrow has a greater length than the others.
Lines 20–24: The
shaftwidthof this arrow has been increased, making its body slightly wider than the other arrows.Lines 26–30: This cyan-colored arrow's
headwidthhas increased somewhat.Lines 32–36: The last arrow has a greater
headlengthas compared to the other arrows.Lines 40–46: These lines create the reference coordinate axes.
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