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Angular orientation

Calling Sequences
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orient3 (phi = angle 1 , theta = angle 2 ) 
rot3 (xa = angle x , ya = angle y , za = angle z )

Description
Note that most of the functions in 3D PyGist accept keyword arguments. These arguments may be entered in any order; omitted arguments will default to a sensible value.

orient3 sets the orientation of the object to (angle 1 , angle 2 ). Orientations are a subset of the possible rotation matrices in which the z axis of the object appears vertical on the screen (that is, the object z axis projects onto the viewer y axis). The theta angle is the angle from the viewer y axis to the object z axis, positive if the object z axis is tilted towards you (toward viewer +z). phi is zero when the object x axis coincides with the viewer x axis. If neither phi nor theta is specified, phi defaults to -pi / 4 and theta defaults to pi / 6. If only phi is specified, theta remains unchanged, unless the current theta is near pi / 2, in which case theta returns to pi / 6, or unless the current orientation does not have a vertical z axis, in which case theta returns to its default. If only theta is specified, phi retains its current value. Unlike rot3, orient3 is not a cumulative operation.

rot3 rotates the current 3D plot by angle x about viewer's x axis, angle y about viewer's y axis, and angle z about viewer's z-axis.


next up previous contents index
Next: Physical orientation Up: Functions For Setting Viewing Previous: Functions For Setting Viewing   Contents   Index
Michiel Jan Laurens de Hoon 2003-04-19