Forums Technical Discussion Rest attribute for Fur, using point()?

Rest attribute for Fur, using point()?

   5214   7   0
User Avatar
negow
Member
27 posts
Joined: Jan. 2007
Offline
 
It works, but is noticably slower than not using any rest pose, which re-populates the fur over the mesh per frame on my animated mesh. It doesn't seem right, as I'd think that populating only once would make it faster, not slower.

So how would you create the rest attribute, if not using the point() with $PT?
 Report
User Avatar
derrick
Staff
329 posts
Joined: July 2005
Offline
 
negow
So how would you create the rest attribute, if not using the point() with $PT?

Appending a Rest Position SOP to the skin geometry is a quick and easy way to create the rest attribute. A Time Shift SOP with a constant frame can be used to specify a suitable reference frame (second input into the Rest Position SOP).
 Report
User Avatar
negow
Member
27 posts
Joined: Jan. 2007
Offline
 
Yeah. That did the trick, thanks.

While I have you here, how would you get the normals on the fur curves to always point to one another? Right now, I'm doing it the ForEach way (point 0 minus point 1, etc. per primitive), which works, but is very slow.
 Report
User Avatar
derrick
Staff
329 posts
Joined: July 2005
Offline
 
negow
While I have you here, how would you get the normals on the fur curves to always point to one another? Right now, I'm doing it the ForEach way (point 0 minus point 1, etc. per primitive), which works, but is very slow.

What do you mean by normals pointing to one another? An example .hip file would make it easier for me to understand what you are trying to achieve.
 Report
User Avatar
negow
Member
27 posts
Joined: Jan. 2007
Offline
 
Sorry, I meant to say, have the normal of every point, point towards the next point. ) The grammar gets confusing. Take a look at the hip file.

Attachments:
alignedNormals1.hipnc (67.0 KB)

 Report
User Avatar
negow
Member
27 posts
Joined: Jan. 2007
Offline
 
To clarify the purpose, I'm not using the actual fur, but rather copying geo the the basepoint (plants, in this case), and using the others for wrap-deforming. The normals need to conform to the deforming and swaying of the fur simulation in order for both copying and wrapping to work correctly.
 Report
User Avatar
derrick
Staff
329 posts
Joined: July 2005
Offline
 
Operations performed in a Point SOP can usually be speed up by re-implementing them in a VOP SOP. In the attached file, your Point SOP expressions have been re-implemented using a VOP SOP. It performs the same operation but will cook faster.

Attachments:
alignednormals1_120-2.hipnc (85.3 KB)

 Report
User Avatar
negow
Member
27 posts
Joined: Jan. 2007
Offline
 
That is very good to know, thanks a bunch for your help derrick.
 Report
  • Quick Links