[Sidefx-houdini-list] Confused about ptransform(), wo_space(), ow_space() and rest position.
ubik.lists at noos.fr
Fri Aug 13 09:14:42 EDT 2010
I'm a bit confused about spaces transforms in a vop surface.
First I tried the transform vop, which uses the ptransform() function.
This one works as expected, from what I understand, in a vop surface,
the current space is camera space, and if I transform the P in the vop
from camera space to object space I get the expected result (same P as
Then I noticed that the rest position node, when no attribute rest
exists, uses a uvspace change which itself corresponds to
The wo_space() and wt_space() function give me the same result, which is
the same as ptransform("space:camera", "space:object").
And this is what I don't understand at all.
The help says for wo_space() : transforms a position value from World to
for wt_space() : transforms a position value from World to Texture space.
What's the difference between these two ? And it looks like they
transform from camera to object space and not from world to
Thanks a lot for clearing things up,
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