Thanks for the links and the blender files, having the blender file makes it so much easier to see what's going on.
What I see is that by avoiding overlap in the weight painting of the two sides of the joint the surfaces attached to the bones simply pierce one another instead of forming an ugly indentation. The downside is that you still see the crease on the outsides of the joint.
- KneeCircled.jpg (16.01 KiB) Viewed 10389 times
I was doing the same thing a year ago,
viewtopic.php?f=3&t=14183 we had a five page thread about it but in the end no one knew how to change the weights in MakeHuman
Mostly for the sake of feeling that I tried everything, I decide to try out mesh deformation cages, which are used in BlenRig 5, which are supposed to produce very good results.
As a starting point I just made a cylinder that encased a leg mesh. I used a stupidly high resolution cage mesh, one of the beauties of mesh deform cages is that you don't need fine meshes, and that because the mesh is low res it is relatively easy to make corrective shape keys as needed. The other wonderful thing is that they are reusable, the same deformation mesh can be fitted to any humanoid body without redoing the shape keys, you just need to line up the joints. In theory you should be able to run the cage mesh through makeclothes and have it automatically fitted to any model. I had hoped to do that with the BlenRig cage mesh but it turned out that mesh contains triangles around the major joints because triangles behave better under deformation, a triangle is always planar while quads often become non-planar when deformed.
Anyway, I started with this:
Bending it 90 degrees gave this:
Adding a very lazy shape key:
Produced this result:
Not too bad considering I didn't do a proper shape key or fine mesh fitting.
A few notes: that I didn't use an optimized mesh which should give better results, I didn't fit the mesh close to the body which would give better results, I only did the deformation bind at level 5, you would use level 7 for production but that takes several minutes of compute time to do the binding, and I didn't put any real effort into the shape key and used the default weight painting. So, I would say this approach is promising.
A blender question, when developing shape keys is there an easy way to edit the mesh in its posed state? Normally when you go into Edit Mode the mesh snaps back to the rest state. I seem to remember something like making a shape key for the posed position and then a second one for fixing the deformation... I have to look into that...