Problem with meshdeform modifier and armature.


I’m having trouble with trying to deform a mesh with an armature and a meshdeform modifier.
I’ve examined the Chinchilla blendfile of Big Buck Bunny for over 2 weeks now and I can not find a solution.

I guess it has something to do with the vertex group called “noMdef” in the Chinchilla blendfile.

When I do something similar, then the armature deforms the “fingers” properly
when “Inv” is selected like in the Chinchilla file, BUT then the meshdeform modifier does not
deform the mesh, as you can see in the first picture.
When “Inv” is deselected then the meshdeform modifier does deform the mesh, but then the fingerbone
does not deform the mesh anymore, as you can see in the second picture.

Could anyone explain this to me please?
Thank you …



I’ve got it to work.

In the Chinchilla blendfile there is a vertex group called “noMdef” : it has ALL the vertexes of Chinchilla assigned to it: in the Armature Modifier of Chinchilla this vertex group is added to the “VGroup” and then “Inv” is selected.

When I do it like that on my mesh, then that does NOT work.

In order for it to work I tried the following:
Instead of assigning ALL vertexes of my hi-res mesh to a vertex group, I assigned ONLY the finger vertexes to a vertex group: and in the Armature Modifier of that hi-res mesh that vertex group was added to the “VGroup” and then “Inv” was selected.`
And now it works!
(The other way around ALSO works : create e vertex group for ALL vertexes BUT NOT the fingers vertexes: and in the Armature Modifier of that hi-res mesh that vertex group was added to the “VGroup” and then “Inv” was NOT selected.)

BUT: it’s totally UNclear to me why in the Chinchilla blendfile the vertex group “noMdef” has ALL the Chinchillas vertexes assigned to it: because when I do it like that, then the fingers do NOT move.

Could this difference have something to do with older versions of Blender?
I’m using 2.48a

Yes “ALL the vertexes” but not all with a weight of 1 !
I think the group “noMdef” must be the sum of all the VertexGroups which deform with the armature

(sorry for my english)

Thanks Kiopaa!!

I’m such an idiot! LOL
Of course…
That’s why I finally did get it to work like the Chinchilla blendfile with only a minor difference: in the Chinchilla blend there’s 1 VGroup for ALL but with different weights, and in my blend there’s 1 VGroup with only the ones that “are weighted”, which eventually comes down to almost the same, hehe, but of course the Chinchilla is a more “smooth” solution.

Well I now know how to go about it and make it work, so thanks!!

I just don’ tunderstand why “Inv” needs to be selected, which inverses the vertex group influence.
So I could create a VGroup with all verts having an opposite weighting and then leave “Inv” unselected, and then it also works.
The only logical explanation I can come up for this is that the Armature Modifier of the hi-res mesh will actually influence a 100% the vertexes that have a weighting of zero, and influence zero% the vertexes that have a weighting of 1.
One would expect it to be the other way around, no?
And this is so badly explained in the Blender manual.
In fact: the "VGroup"field of the Armature Modifier is not explained at all in the manual.
The "VGroup"field of the MesDeform Modifier is being explained in the manual:
it says :“The VGroup: text field is used to indicate that only the vertices in the specified Vertex Group will be affected by the Deform Mesh Cage.”
To me that sounds that vertexes with a weighting of 1 are being influenced a 100%, which turns out to be not the case for the "VGroup"field of the Armature Modifier.

Anyway, you’ve helped this stupid noob A LOT!