corrective shapekey troubles

I’m trying to build some corrective shapekeys for a rig on mine. And I am having a hell of an annoying time at it.The topology isn’t optimal but that’s not even the issue.
The issue is what I believe is called “crazyspace”
I’m trying to correct some deformation in the shoulder area, when the arm moves forward, towards the chest for instance.
The problem is that when I add a new shapekey and start editing, grab the vertex around to move them to a more natural position for that pose, it just doesn’t work!!
the vertex do NOT move as they should, they jump all over the place.
I have tried a few things for display, regarding the armature and subsurf modifiers.
Such as displaying the effects of the subsurf and armature modifier in editmode.
Whatever combination I choose, most of the times the vertex seem to move as if the character is standing in it’s default “T” pose/editmode. But sometimes the verts move so eratically that even this doesn’t explain it.

How the heck should I make those bloody coorective shapekeys? when I can’t even predict how the vertex will move?

ps.
done another test just now, before posting, and if I disable the “apply modifier to editing cage” button, at least the vertex move as they should again, but this is very akward to work with.
I’m using blender 2.45, but wasn’t this whole crazyspace issue fixed a few versions ago?

anyone with suggestions?

I think the developers started talking about fixing crazy space a couple of versions ago, and came up with some testable concepts, but it’s not in 2.45. Maybe the next version?

funny, I was rewriting the Softbody page in the wiki and got to the point where I realized you can have shape keys on softbodies and thought “Hey, i wonder if you could use a shape key to correct minor collisions?” but have better things to do. If you figure it out, let us know. Thanks.

To me, your issue sound like you have too many things going on - bone deformation, subsurf, shape keys, and, outside of some magic (envelope?) boundary, Blender gives up and releases the vertex, so that it jumps out there.

I feel your pain FreakyDude. Modeling at the end of the chain of order is always annoying.
If you find a way to overcome this , let me know too! Hell just post it on this thread and let everyone know.

With regards to the ‘crazy’ verticies, go into editmode and select them. See what bones have weights on them in the transform properties panel.

Well i don’t really need to do that, since I know pretty much exactly what bones have what influence over what vertices. I tweaked most of it in edit mode and then mirrored them to the other side. I’m updating an old rig of mine, so I know how everything works and what is assigned where.

@ Papasmurf: Well I am rather confused about this, since I’ve been reading a little in the “introducing character animation with blender” (I admit I kinda only search for specific topics when I get stuck with something) and there is a section on using shapekeys to do exactly what I want, to correct how the shoulder looks when deformed, on page 234 to 237.
The technique he describes is exactly the one I tried, down to the letter!! so it should work.
I don’t use envelopes, it’s all vertex groups. There’s no other shapekeys around either, I deleted all the old ones.
Of course my rig isn’t his rig, it is a sound custom tailored rig, and does what it should very well, but still there’s nothing in there that should cause problems.
The forearms have IK constraints, but their influence is set to 0, so I can rely on the rotation of the upper arm (hmm, maybe i should try removing these constraints for now), and all the driven constraint links have been removed, to get a clean start.
In theory everything SHOULD work…
I’ve made a test deformation which should work fine when the arm rotates, but now I don’t get it to work by having the shape driven by the upperarms rotation, hmmm, but then again, I may have set the wrong rotation for the driver. . . . . . .
plenty of stuff to check and do…
There’s only a few shapekeys I want to use to help some ugly deformations (they will need extensive testing though), and there’s around 30 more I want to make for the face, but I’d rather not start on that until the body deforms better…

I’ve run into the same prob, FD, trying to tweak a sculpt even subtly while a bone is influencing the verts is a crap shoot. Shoulders are particularly in need of help in this regard, but I gave up on shape key correction and just added some “corrective” bones (more like muscle-pullers) that I can use to reshape the deltoid, traps and lats areas. For elbows and knees I carried this a step further and have corrective bones driven by the rotation of the main bones via pydrivers.py scripting. Shape keys are also somewhat limiting imo, unless you want to create a whole slew of 'em to cover nearly any possible position.

I often do some subtle re-sculpting to compensate for deformations in poses, but I’ve gotten to where I can estimate fairly well what I need to do in the “ref pose” state to make it work in the posed position. By setting keys down the timeline for a pose and keeping the ref pose keyed at frame 1, I can go back and forth fairly quickly.

Shoulders are a problem because besides crazy space, you deal with combined bone rotations. The captain Blender example only considers one movement and there should be at least four.

About crazy space I just tested SVN and the problem has been corrected. You can now select a vertex and then press G, X (or Y or Z), arrow and it behaves as expected.

For shoulders this might help. I have yet to find out what new features are there to take advantage of.

I’m starting to wonder if I should bother with them at all, the real problem comes with the biceps and the chest when moving to the front. The character has evolved from a N64 stat char so it would be UBER simple and only ment to animate the body, to a full blown character rig with facial features and all.
It’s the rig in my sig by the way. I’m updating it, I’ve been doing some test/try/learning animations with him and found some points that bothered me, I’ve got most of them covered, but with subsurf on some of the ugly deformations become apparent. So I thought I’d use shape keys to correct them, since my early experiments with deform bones didn’t really work out. The topology is as basic as I thought I could get away with and get clean deformations, and for most part, this seems true… but, aah wtf, I’m tired, my head is spinning and I don’t really recall what my point is.
Toloban, chipmasque, if you could look at the rig in my sig, the shoulder setup didn’t change much, do you believe I should change something there? and biceps area?
I’m kinda stuck between getting the body done first or leave it as is and advance to redoing the shapekeys for the head.