View Full Version : Direction Constrain problem in Softimage XSI 5.0

05 May 2006, 09:10 PM

Iíve got a small problem in Softimage XSI 5.0 and I hope someone can help me.
Iíve got an eye and the texture projection is set with a Direction Constrain to a Null. So far, so Good.

But when Iíve translated the Null and put it back to his original place (0,0,0,), the Texture projections are slightly rotated. Can someone tell me how I can let the texture projections to follow the Null in Rotation but not to let it ďslipĒ?


05 May 2006, 10:54 PM
Did you apply the constraint with constraint compensate turned on? It might have made an offset which is visible at this extreme angle.

05 May 2006, 01:23 AM
a direction constrain can only take care of a plane orthogonal to the direction, which means the rotation (roll) along the direction axis is undetermined and left to guesswork (XSI's heuristics).
to stabilize it you need at least two vectors, read: you need an upvector to resolve the whole transformation in a stable manner.

05 May 2006, 09:31 AM
yes, Iíve turned the constraint compensate on while applying the constrain. Was smart enough to do that :)

ThE_JacO, it sounds logical but can you explain to me how I can do this exactly. I've tried to put a up vector on it, but because its not a joint/rig, he won't do it.

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05 May 2006, 09:31 AM
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