How to parent one vertex group to a specific bone in Blender 2.8

Question

I made a bunch of vertices (in this case in the grease pencil mode but it doesn't matter how in practice) and I want to parent them to a specific bone.

To add the vertices to the individual vertex groups I clicked on the parent "Stroke" object, scrolled down to "Vertex Groups", clicked the + button and created four vertex groups. Then in edit mode, I selected the vertices I wanted in each group and pressed "assign".

I then made a bone as a separate object and created four bones.

Now what I want to do is pretty simple, I want to assign the vertices in the four vertex groups to the four bones.

However, this is proving to be a little challenging. Clicking a vertex group does not highlight the vertices. I have to be in edit mode, click on the vertex group and click "select" to select the group of vertices.

Then when I go into object mode the whole object is selected so I do not know which vertices are selected.

Even more confusing is that to parent this vertex group to a specific bone feels impossible because when in object mode, clicking on one bone and shift selected the mesh object selects both *not indicating which individual bone is responsible for the vertices).

So the real question is: How do I know which bone is responsible for affecting vertices. In the following image - how do I know which bone is responsible for affecting the vertices in red?

and

How do I simply parent a vertex group to a bone and keep track of that, one bone at a time?

Thanks for your help

Answer 1

In my opinion you’re not working with the good method, if you were you would not ask some of these questions, but to answer:

I don't think there's any way to see what is the bone affecting a group of randomly selected vertices, because for example a group of vertices may be affected by several bones and each will have a different influence, so I it may be technically possible to display them but it won’t help a lot.

That said, you can see what bones affect one particular vertex, and how much they affect if, if you select the vertex and open the N panel > Item tab > Vertex Weights.

It's a bit tedious though and I don't think that's what you want.

The easiest way to know how bones affect vertices: Select your armature, switch to Pose mode, then shift select your object, switch it to Weight Paint mode, then select a bone and visually see its influence on the mesh. Also in that same mode, if you select a vertex group in the Vertex Groups list, you’ll see what part of the object it enlights. But you may miss some small influences because at a low value the weight won’t be visually noticeable.

But as I say I’m not sure you use the good logic to rig.

When you parent your object to your armature With Automatic Weight, the vertex groups will be automatically created with the name of the bones that control them.

Once done you can check the bones influences, and you can correct it, either in Weight Paint mode, or giving more or less weight to some vertices with the Assign or Remove button on the bottom of the Vertex Groups list. Or even use the N panel if you like this mode, but again, a bit tedious.

You can always create an additional bone. Give it the name you want. If you want some vertices to be affected by this bone, select them, create a new vertex group with the name of the bone, and click Assign. As the mesh is parent With Automatic Weight this vertex group will automatically be controlled by the bone that has the same name. And again you can play with the weight value to increase or decrease the influence.

You can also create a vertex group and create its bone afterwards, as long as it has the same name as the vertex group, it will control it.