PDA

View Full Version : XSI 5.11 Rigging and skeleton difficulties


Archvilell
02-08-2007, 05:18 PM
I'm having some difficulties setting up a rig/skeleton for a pair of arms for a game my friend and I are making. I bought a Digital Tutors disc about XSI and game development and it hows how to create a rig, but it makes use of XSI's premade biped guide and converts that into a rig/skeleton (I still am not clear on the difference). So the disc doesn't show me how to set constraints or controls to an existing skeleton.

I tried using the guide like the disc said, but I only need the two arms. So I deleted everything else except the arms, but there must be some constraints that didn't delete, because I can't rotate the arms at the shoulder - it won't move at all. So I tried somethng else.

I next used the Biped Rig (not the guide created through the Animation toolbar, the rig created through Model - Get Primitive - Model - Biped Rig). I deleted everything but one arm, enveloped the mesh and positioned it, and everything works great. However, I can't animate it. For some reason, I can't set keyframes on the effector of the arm bone to move the hand around. I set a keyframe at frame one in the first pose, slide the time bar, move the effector into the next pose, and the key button is still green, not the pale yellow it should be. If I click it anyway, it looks like I set a key, but nothing happens when I move the slider.

The bone structure is this, from top down:
Bicep bone - forearm bone; wrist bone; three bones in a chain for each finger.

Everything is parented together and enveloped nicely, but I can't animate.

Please help me; I've looked through all the books I have about this and nothing helps. The books just tell me how to make character guides and don't say how rigs work.

Thanks in advance,
Ben Day
Full Auto Labs

Sil3
02-09-2007, 12:58 AM
I tried using the guide like the disc said, but I only need the two arms. So I deleted everything else except the arms, but there must be some constraints that didn't delete, because I can't rotate the arms at the shoulder - it won't move at all. So I tried somethng else.

You deleted the GUIDE or you deleted after making the skeleton? Deleting things from the XSI Biped Rig should always be done after creating the Rig, dont delete things in the Guide Rig itself.

When you press Make Rig from Guide what XSI does is perform a series of scritps to build the Animation Rig using the Guide positioning and options as a guide :)

If by any chance the script cant find something, usually it just stops there.


I next used the Biped Rig (not the guide created through the Animation toolbar, the rig created through Model - Get Primitive - Model - Biped Rig). I deleted everything but one arm, enveloped the mesh and positioned it, and everything works great. However, I can't animate it. For some reason, I can't set keyframes on the effector of the arm bone to move the hand around. I set a keyframe at frame one in the first pose, slide the time bar, move the effector into the next pose, and the key button is still green, not the pale yellow it should be. If I click it anyway, it looks like I set a key, but nothing happens when I move the slider.



It could be a lot of things, without seing it it's just shooting in the dark, and you aren't animating the GUIDE by any chance are you? The GUIDE is the RED rig, this is only to be used as a guide and nothing else...

...another thing... if you only need an IK Arm why are you using the Guide to build it? Simply make a 2D Bone Chain for the Arm and 3 other Chains, one for each finger, done.

In XSI any Bone Chain is automatically an IK/FK Chain, if you never make Keyframes on the Effector and only the Bones, it behaves as an FK chain, as soon as you place a Keyframe on the Eff it will take IK as it's default behavior, wich you can then control with the IK/FK Slider on the Chain PPG

Archvilell
02-09-2007, 02:12 AM
I guess I'm making things too complicated. I have dropped the idea of using the Guide and turrning that into a rig. After your post and reviewing the cds I have, I don't need the extra complexity of a guide.

My tactic so far was to use the Biped Rig because I assumed it already constraints and such set up for me to better animate with. I didn't really know why I needed constraints; I just figured having them was better than not having them, and since I don't know how to make them, I would have the computer do it.

I now have decided all I need is a simple set of bone chains. I think I can get this to work now. I still haven't figured out why I can't animate the effector, which kinds of bums me out. I like to know why stuff doesn't work so I can fix it later if it happens again.

I'd like to include the .scene file so you could tinker with it as you'd like, but the forum doesn't like that file format. I was going to put them in a .psd so you could flip through the layers, but the file was too big. So I split them into separate jpg images, but the size was still too big. The file size cap on these forums is too small to be of any use.

I guess the root of my problem is I still don't know how a rig works and how to set one up. If I knew that, I could probably have avoided this. I'll post again with how my new idea goes. Hopefully well.

Thanks again,
Ben Day

toonafish
02-09-2007, 08:18 AM
I still haven't figured out why I can't animate the effector, which kinds of bums me out.

You can't move the effector? You can't create keys for it? Or the skeleton doesn't move when you translate the effector ?

if the skeleton doesn't move it could be you have created keys on the bones and xsi assumes you'll be using FK instead of IK.

if you can't create keyframes it could be you don't have the Translate or Rotate tool active when you hit the "k" hotkey.

janimatic
02-10-2007, 11:56 AM
You deleted the GUIDE or you deleted after making the skeleton? Deleting things from the XSI Biped Rig should always be done after creating the Rig, dont delete things in the Guide Rig itself.

When you press Make Rig from Guide what XSI does is perform a series of scritps to build the Animation Rig using the Guide positioning and options as a guide :)

If by any chance the script cant find something, usually it just stops there.

I don't think that's completely true.
I think the script is looking for generic parts but if , for instance, you delete a finger from the guide, it should work. It produce a clean rig in case you need to rebuild it.

Archvilell
02-14-2007, 04:40 PM
Fish, what I meant was I could move the effector, but when I hit keyframe (with the translate tool acive like it should), the key icon does not turn colors. It also does not put a little red tick mark on the time bar. When I move the slider bar back and forth, the piece does not move.

It was very strange and weird, and I still haven't figured it out yet. However, I made up my own skeleton (better for me anyway; I gain experience with skeleton setup), and everything works just fine. If I run in to it again, I'll make sure to better document it.

I do have another issue though. I am rigging a pair of arms and a rifle to reload the magazine, and I'm getting frustrated with having to continually make minutial changes to the position of the magazine to follow the hand. I am thinking there is a better way to set up the heirarchy so that the hand follows the magazine perfectly.

Maybe this can be solved by rigs, and not using direct parent-child. I don't know. I was looking for tips on how to accomplish this. Right now, I have the typical hierarchy for an arm:

bicep-forearm: wrist: finger bones

where the - means same bone chain and the : means a break. However, the right arm is a bit different; I parented the wrist bone to not only the fingers, but the main bone of the rifle as well. That way I can rotate the wrist grasping the weapon to rotate the weapon too. That works pretty well, but I'm wondering if I can do something similar to the left hand and the magazine.

I want to be able to move the hand independantly of the magazine and have the arm follow it (so the forearm is parent of the wrist), but I want to be able to move the magazine and have the wrist and forearm chain follow it. I can't make the magazine the parent of the wrist because I'll lose the arm hierarchy, and I am pretty sure things can't have two parents (I tried it with boxes in a new scene). Anyone have any tips on how I should proceed? I have most of my animation done, but it would be so much simpler and well worth the lost time to fix this issue; I'm going to have many more animations with the hands and magazine.

Thanks,
Ben Day

CGTalk Moderation
02-14-2007, 04:40 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.