proper mesh geometry for animation?

Isis' Minion

Hi, i was wondering if you guys might have tips for me on this particular topic.

I have made my model and rigged it, but the shoulders and crotch area tend to give me trouble when they are animated (shoulder gives problems with arm from straight down to straight up and crotch gives me trouble when the legs are spread wide).
I am using a standard biped with 3 spine links for the rig.

Is the geometry in my problem areas set up right for animation or should i make some changes?

All input will be greatly appreciated, since i'm doing the rigs for a school project (making a 3d fighting game ) and i want to implement this model into UT for my portfolio...

here you can find 2 of the animations i tested my rig with:
Standard Max walk cycle (10 steps)
Wild dance

and here's a wire of my model (if you need additional wire shots, let me know):

KDR_11k

First off I'd say the model could use a whole lot more shape, especially the arms. If your budget is that low remove some of the sides from the arms and legs. The crotch would deform better if you put more attention into proper flow (i.e. have the edges flow along/perpendicular to the shapes, muscles, folds, etc). Currently your cuts are all parallel, you should rotate them.

Isis' Minion

Thanks for the tips. I started out fairly low detailed because i wanted to practice rigging and modeling good geometry for animation, so that i can apply the things i learned from it to my future models. I will go look through other people's wires and try to change the edgeflow as i see fit.

Here's the particular stance that gives me trouble with the leg/crotch area. The stance comes from a ninja-esque character from the school project.

MoP

Yeah, you need at least another row of edges around the leg at the top. Also it looks like your pivot point for the upper leg bone is too low... see if you can find some anatomical drawings or images where the skeleton is shown overlaid onto the human body shape, and try to match your rig's bones to the places that real bones are located.

Rick Stirling

Ok, I've knocked this us, I hope it can help a little.

The body can be considered to be built in sections, that all flow into each other. No parts don't flow!

You built the arm by extruding out from the body, but you want to extrude a shoulder out, then an arm DOWN from that.

Isis' Minion

Thanks for the info, guys.

MoP, I'll look into the skeleton alignment, good point.

And Rick, thanks for the drawing, i usually go about extruding the arms straight out of the torso, then use the cut tool to define the shoulder shape. Though, i am only making the rigs at our school project, someone else is modelling, but i'll pass the info his way as well (he made the model with a 90 degrees corner between arms and torso).

I'll post my progress as i continue experimenting. Pretty much a rigging and animation rookie, so i appreciate the help a lot!

PS: another small question...The ninja-esque character has a piece of cloth hanging down between his legs from his stomach. What would be the best way to animate that piece of cloth nicely, so that it does have animation and doesnt go into the legs?

KDR_11k

Additional bones?

Rick Stirling

The only way it won't clip into the legs is to hand key every animation, or use a cloth sim. Or use a cloth sim and then key those verts.

KDR_11k

I doubt the engine can support vertex keys but most fighting games have bone-based cloth simulation built in.

Isis' Minion

We're working with Virtools, so baking cloth sim to keys might be possible.

KDR_11k

Okay, at that polycount vertex animation should still be reasonable. At the polycounts fighting games use nowadays (anywhere from 10k upwards) it would kill the framerate and RAM.

Frankie V

If you can bake the animation then using the skin modifier instead of physique might be a better option for animating for effect. You can use the morph angle deformer to tweak out your sequences then bake the results.

Isis' Minion

While exporting some files today to the Virtools format, i noticed that the exporter converts Physique to either Skin or Morph...this could have probably saved me some time ._.

Anyways, both characters for the game are rigging up a lot better now. Thanks for the help!

deadflowers

Evaluations aside, your deformation is not that bad. Before you make further alterations, try a test UV map to see the "real" result. Don't readily evaluate the deformation behavior by its underlying appearance, as the general user will not know the difference. If it looks good in skin, leave it be.

Otherwise, if it still looks weird, and you have to maintain a quota regarding the number of polygons, axe the nipples and use those polygons to embellish the groin with a few more triangle. The UV map can have the impression of nipples added to it.