skinning armor pieces?

Rekmar

hello there,
I'm working on a character that has some armor pieces.
What I want to achieve is that the armor pieces go as tight to the model as possible but making them feel as rigid as possible, to resemble real armor.
My model is being rigged in a "T" shape.

Here is a WIP pic of how the armor looks:
http://www.shalinor.circustent.us/elium/screen_shots/armortest2.jpg

Now comes the problem. As you can see, on the shoulder I have the shoulder pad that consists of 3 plates on the outside of the arm. Now, if I make them all rigid and only react to the upper arm bone, they feel fine, but when I rotate the arm so it points down, all the armor goes down and the top of the shoulder goes without armor, unprotected.

So what I want to do is make the 2 lower plates go down 100% with the arm, and the top one rotate abit on its own place to keep the top of the shoulder covered.
For this I tried selecting all the vertices of the plate from the top and making them only have like 0.3 of weight on the upper arm bone. This makes the plate rotate abit less than the other ones, but it seems as if it was being shrunk (in one axis, along the arm) as the arm rotates more, and thus, it doesn't feel at all rigid.

Is there a way to make the upper plate rotate abit less than the lower ones without being shrunk?
I am using 3dsmax btw, with biped and skin.

Any tips for this kind of thing? I've never rigged/skinned armor before, is there any useful tutorial for this?

Thanks in advance

[edit - fixed link]

Valandar

404 on the picture link

scanning_factor

Not sure what engine you're doing this for, but you might try and set up some helper bones, either procedural or not. Usually when im doing characters with armor, i tend to treat that sort of thing as almost a separate character and build in special rigging considerations for it. I'm not sure how easy it is to do in Max, in Maya i would just set up some sort of a math rig for it.

Rekmar

sorry for the wrong link, it's fixed now.
I'm making this for the Nebula2 engine, but that doesn't say much by itself. What does say much is that I'm using the same skeleton as the character uses, and (since our engine can do it) we're making bones be shared among characters (we use paperdolling), which means I can't go around adding more bones, not to mention I already have a decent amount of animations done, which makes the bone thing an option that won't be happening.

hmm any other ideas?

scanning_factor

there's really no way to do what you're trying to describe with just weighting. a piece that's supposed to appear rigid really should be weighted 100% to one bone. Unless you can use some sort of morph target, you're probably not going to get great results. The only other sort of suggestion i could make would be to implement some sort of stretchy bone solution, but that's dependent on your engine's support of nonuniform scaling. given that you're only working with a specific hierarchy, it's going to affect whatever else is bound to the joints as well, so that's also probably not an option.

Asthane

Yep, if you don't want it moving all the way down with the arm, I would seriously consider skinning it 100% in the up position, maybe add some geometry to make it look like it's supposed to be there (Or add another piece of armor to cover the top of the shoulder and let it this one move with the arm.)

Rekmar

well the engine won't support morph targets either, and I can't really go around scaling bones because I can't add more bones either

hmm my latest test involved abit of manual mesh adjusting, resulting in this:
http://www.shalinor.circustent.us/elium/screen_shots/armortest4d.jpg
this is how it looks on 100% weight on the arm, it looks abit weird when the arm goes up, but not too bad, and arms won't go up that often, nor will it be a slow movement to care for, so I can just leave it like that.

now, I'm unsure if the engine will support it, but it seems that a joint angle deformer (or maybe one of the 2 other inside-skin deformers) can do what I need. I'm just messing with it for now so I can't know for sure yet.

Does anyone have more info about the skin deformers?
any help on this will be greatly appreciated

Downsizer

use sockets? attach the peices at a tag geometry point. have the tag follow the vertex/edge/whatever movement.

Eric Chadwick

How many bones do you have? Do you have clavicles? Can you show a shot of the skeleton and the wireframe together?