blendShapes

[philmc]

Here are a few things to keep in mind when creating blendShapes for your characters.

Typically blendShapes get created after the character has been bound to the rig. The problem that arises is that when we set one of the targets to 1, the geometry stops deforming with the rig. This is because the blendShape is overriding the skinCluster; it is being evaluated before the skinCluster, so it appears that our geo is no longer affected by the rig.

The way around this is to either create the blendshapes before making the skincluster (rare) OR reverse the input order of the BS and SC.

Before you create blendShape targets, be absolutely sure that the geo (usually the character geo) is in a neutral position. Best way to do this is to select any deformers (like a skinCluster, cluster or lattice) and set the Envelope for that deformer to 0. This puts the vertices at their default positions. Then, create the blendshapes in the normal way.

Next, delete the non-deformer history (so long as it doesn't mess up some other aspect of your rig). Edit/delete by type/non-deformer history. This will delete all history but the skincluster and BS.

With your character geo selected, go up to the top of the interface and look for the Input and Output icons (between the "snap to" magnet and the render icon). LMB click on the Input > and choose the last menu item, All Inputs. You'll see the BS above the SC... MMB drag the top under the bottom line (if it doesn't work, try MMB dragging the bottom above the top). You should end with the SC above the BS in the input window. Now the SC will evaluate normally and include all that's happening on the BS when you switch on one of the targets.