While working on character’s head, I ran into this problem again when skin cluster won’t work after adding blend shapes. I checked in my notes to see what’s the proper order of deformations, and here is the list:
- skin cluster;
- sculpt, clusters, wire etc;
- blend shape;
- tweak node.
The nodes on top of the list are calculated last, while the ones on the bottom are calculated first. If the geometry appears not to be moving with skeleton, as happened in my case, that is because blend shapes are being calculated last, and should be moved to the bottom of the list. Tweak node will remain even after deleting nondeformer history and should be best left at the bottom of the list, thus being calculated first.
To reorganize the input node list, click on inputs icon in main toolbar, and choose all inputs. Then the window shows up, listing all the inputs of the selected geometry. Middle-mouse drag the listed items to change their order. It should look something like this:
I have two clusters for each eye, blend shape and skin cluster. This geometry, which is a low-resolution version of the head, also has a wrap deformer output, because it deforms hi-res version of the head. Luckily, I remembered to check the input order list instead of panicking and wondering why my deformers stopped working.