I followed this short and sweet tutorial for how to apply automatic weights in Blender 2.92, with the knowledge of what a weight is in general (an assignment of a bone to a specific part of the model and how heavily it influences it), but unfortunately my model doesn’t animate at all with any of the skeleton bones when I move them after doing the proper assignment (Ctrl P, then click with Automatic Weights).
Can someone please explain what I am doing wrong in my model compared
to the tutorial’s example?
This modeling does not have a proper edge.
The joint works only when there is an appropriate edge in the area where the bone is located.
Automatic weight paint is the process of forming a Vertex group in the area where the bone is located.
However, the object does not work properly because it does not have an edge in the appropriate location.
As pointed out, it’s your understanding of the basic definition of weight painting that caused the problem.
Weight Painting is the assignment of each vertex in a mesh, at a specific level of influence, to a bone or bones.
So with Automatic Weight Painting, Blender will take each vertex and basically assign it to the nearest bone within it’s general area. If there are a few bones near the same vertex, then the assignment will be averaged over them, depending on distance.
Of course if there are no vertices (the problem in your case), then there’s nothing to assign and hence nothing that the bones can move.
Automatic weight technically works with your model, however there are multiple problems with it. First, model is composed of multiple disconnected fragments. Auto weighting can struggle with such models and even fail to assign some pieces. Either learn some better modeling techniques such as box modeling or edge extrusion, or be ready to manually assign missing pieces through Edit Mode - Object Data tab - Vertex Groups menu - Assign. Second issue is with your armature. Hierarchy in the arms goes in reverse direction. Parent order should go from shoulder to hand. Automatic weights also take bone hierarchy into account, so it better to be unbroken.
Awesome! The videos explained it already too from what I understood, but a straightforward answer without all the extra info/details is also very appreciated.
