Skeletal animation: only 4 bone assignments per vertex?

[Elusive Pete]

Just ran across this in the docs. Apparently Ogre only supports 4 bone assignments per vertex? I was wondering if this is definitely still the case, or if it's changed since the docs were updated?

It's not particularly important, as 4 per vertex is usually plenty. I'm just curious.


Thanks.

[haffax]

This is still the case. Else the cost-usefullness ration where too low. That said, you can recompile Ogre after changing the maximum value of bone assignments in your OgreConfig.h. I didn't try it myself yet, so I don't know if this works well, but theoretically it should.

[epopov]

If you do that, I think (but not sure) that you will also need to modify the vertex shader used to do hardware skeletal animation.

[sinbad]

It has the advantage of being able to be squished into a single 32-bit value per vertex (1 byte index per assignment) which means your vertex buffers are not bloated too much when supporting hardware skinning. And as you say, 4 bones per vertex is plenty, a lot of engines still only support 1.

[xavier]

If you do that, I think (but not sure) that you will also need to modify the vertex shader used to do hardware skeletal animation.

The Ogre sample materials include vertex programs for 1, 2 and 4 weights per vertex. Yes, you would have to do a separate vertex program for each weight not covered, since it is not a general technique (unless you are targeting only GPUs that support vertex program instruction branching).