How to scale skeleton parts?

[hwy1992129]

I go through the code in gloss_skeleton. It looks like the variable zs controls the shape of the skeleton, but how to scale it in x,y,or z direction...?

[MarilynKeller]

The skeleton model released with OSSO does not suport the bones rescaling. To change the shape of the bones, you can refer to the demo of the full skeleton model on Silvia Zuffi GitHub : https://github.com/silviazuffi/gloss_skeleton. The demo 'python show_skeleton.py' shows the bone shape spaces.

[hwy1992129]

I check the code in gloss_skeleton, but I don't understand how they do the scaling... I only find the variable zs could change the shape, but zs can have more than 3XN dimensions, like 4XN, 5XN, which doesn't looks like x,y,z....

[MarilynKeller]

You are on the right track. zs is not a simple scaling, but a per bone synthetic shape space of dimension N (N=7 if I remember correctly). The shape space of each bone is illustrated here.
So by setting values of zs you can change the shape of the bones. The code then computes the necessary offsets between bones to avoid overlap.

[hwy1992129]

The image does show the part scale on x,y,or z, but I haven't figured out how to do it... I ask a question in gloss_skeleton and get no response...

[MarilynKeller]

The shape space used in the GLOSS model is described in the SMAL Paper page 4 "Shape deformation space". I think you can scale the bone i by x, y or z by changing respectively zs[i*7+0], zs[i*7+1] and zs[i*7+2]. I can not test at the moment unfortunately.