Planes in Python


Planes are represented by a Plane structure. Planes can be thought of as a zero-based, one-dimensional list containing four elements: the plane’s origin (point3D), the plane’s X axis direction (vector3d), the plane’s Y axis direction (vector3d), and the plane’s Z axis direction (vector3d).

plane contains [pointOrigin, vectorX, vectorY, vectorZ]

It is easy to forget that there is a specific geometric relationship between the axes. With Planes, the Y axis is automatically oriented 90-degrees to the X axis. The X axis is the only axis that can be easily defined. The Y axis is made orthogonal to the X vector, and the direction of the Z axis is computed from the cross-product of the other two vectors.

Planes can be constructed in a number of ways. One common function is PlaneFromPoints:

import rhinoscriptsyntax as rs

corners = rs.GetRectangle()
if corners:
    plane = rs.PlaneFromPoints(corners[0], corners[1], corners[3])

print plane[0] # origin point
print plane[1] # x-axis vector
print plane[2] # y-axis vector

Planes can also be created using the CreatePlane(), PlaneFromFrame, PlaneFromNormal, and PlaneFromPoints functions.

Plane also have a number of properties that can be used to get or set the individual values in the Point object. In the example below the .Origin, .XAxis, .Yaxis, .Zaxis are used:

import rhinoscriptsyntax as rs

plane = rs.PlaneFromPoints([-2,-5,0],[1,2,0],[-3,3,0])

print plane.Origin # origin point
print plane.XAxis # x-axis vector
print plane.YAxis # y-axis vector

plane.Origin = rs.CreatePoint(3,4,5) # Changes the origin of the plane.

print plane.Origin
print plane.XAxis # x-axis vector
print plane.YAxis # y-axis vector

To change origin of a Plane, simply assign a new value to the .Origin property.

Use the Python for iterator to walk through each point coordinate in succession:

for p in plane:
    print p

RhinoScriptSyntax contains a number of functions to manipulate planes. See Lines and Planes for details.

Also, please see the Python primer Section 8.5 Planes.