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Richard Hebert
11-25-2010, 08:24 PM
I'm importing BVH files into LightWave and encountering problems repositioning the bones. The BVH rig uses gimbal bones and I can't manipulate the joints properly using the "joint" tool. How do I manipulate these kinds of skeletons in a straightforward manner? The mesh and BVH files are exported from Poser. Any thoughts are helpful and as always, very much appreciated.

Richard

OnlineRender
11-26-2010, 01:08 AM
Sorry not entirely sure what you are looking for . RH , is MR RIG . :rock:

are your resting the bones once you have positioned them ? . BVH data can be messy sometime ,are your creating a null first then importing the rig ?
You can export the rig from layout into modeler and tweak them there .
Hope this helps .

Greenlaw
11-26-2010, 03:14 AM
The 'quick and dirty' way to do this is to convert your .bvh bones to joints using the Bone Type tool. The command may be hidden or you may need to add it to your menus. Once you have the command, select all your bones (easiest way is to use the Bones Item List next to the Current Item list) and then select Bone Type and then select Joints.

Once you're in Joints mode, click on some joints and look at the keyframes in the timeline. You'll notice that some Joints have keys but the gimbal joints only have a single keyframe at frame 0.

If your .bvh rig has a T-pose at frame 0, go to it. If not, there's more instructions for this later.

To edit the rig to fit your mesh, do the following.

Turn on Autokey.

At frame 0, you can move any of the Gimbal Joints to the position you desire for fitting your character, and as long as you stay in Joints mode, this will be fine. If, however, you switch back to ZBones after moving the Joints, you will have problems because ZBones does not acknowledge new rest lengths or rotations from Joints placements. But like I said, this was the 'quick and dirty' solution, and if you stay in Joints mode, this will probably work out fine. Because of this, when editing Joints to fit your mesh, use only the Move tool, and do not use any of the Bone Tools or use Rotate; in many cases these tools only make sense with Bones and not Joints.

(IMO, there's are very few reasons not to stay in Joints mode because you have more rigging options available when using Joints. The only time I switch to Bones right now is when I need to export the rig to an FBX file. This is because Lightwave's FBX exporter will mess with the Joint names hierarchy when you export while in Joints mode, but it will leave the names alone in Bones mode. At least, this has been the case for me.)

Now if your .bvh does NOT have a T-Pose, you should add one. I think you can do this with the free BVHacker or Animeeple. For example, I use iPi Studio to create .bvh data, and by default it outputs all bones zeroed out in the first frame, which looks like a pile of bones on the floor. I typically bring this into Animeeple, set the T-Pose there, and then export an FBX or a new .bvh depending on how I want to use the data. (Note: I think the latest iPi Studio has the option to include the T-Pose now. I'll have to check on this.)

Remember, when you move the Gimbal Joints at frame 0, you will need to re-rest the bones for your mesh. The 'Q&D' way is to select all your bones (Bones Item List) press Ctrl R and then R.

Now of course if you are moving moving or rotating the Gimbal joints to edit the motion (as opposed to editing the rig to fit your mesh,) you would not re-rest the bones. To edit the motions, you can edit the Gimbal joints (easiest) or edit the motion joints, in which case you will probably want to use the Graph Eidtor and select all the key frames and edit them at once.

Or you can use IK Booster, which has some good tools for editing a lot of frames and blending them in and out of the original mocap data. At this point it becomes a subject too big for a forum post, plus I'm not an expert in this area, so I will stop now.

Well, that's my five minute lesson for today. Hope this helps. :)

G.

P.S., one of these days I will do some proper tutorials for making 'garage productions.'

Richard Hebert
11-26-2010, 08:54 AM
Thanks greenlaw,
That is a very detailed response! I've never used joints, not sure until now how they affected rigs with bones. Formal training would really come in handy for these issues. At 45yo. and a full time job, I rely pretty heavily on others' experiences. Thanks for valuable info. There are a lot of rigging tutorial DVD's out there. Is there one that you would recommend in particular? I do not have a lot of cash to throw around at the moment. I normally would use IK Booster to manipulate the bones but somebody at NewTek thought that the Mac version didn't need access to the undo feature when a bone gets moved or rotated using IK Booster. Also, can't copy and paste data between rigs either. Thanks NT for the rapid response from my phone call to your tech dept. 3 months ago...NOT.

Greenlaw
11-26-2010, 11:49 AM
I've only been using Joints in the last couple of months, ever since my wife and I started our latest short film project. I avoided using Joints for a long time mostly because this feature has been thinly documented. (Well, that and we're actually using Maya for CA at work now.) What finally convinced me to use Joints for my own project was the advice and videos by Lightwave user Rebel Hill. I highly recommend his videos, both the free and commercial ones.

I think his Understanding Lightwave and FBX video has a good overview of Joints as they relate to mocap rigging. You can see it for free here:

Understanding Lightwave and FBX (http://www.rebelhill.net/html/lwandfbx.html)

You might want to check out some of his other videos while you're there. His Rigging videos are top-notch, though most of it is about rigging for keyframe animation and only a small part of it is relevant to rigging for mocap (which I've learned can be quite different from rigging for keyframe animation.) Still, very good info and an excellent presentation.

I've only been using IK Booster recently too and mainly for editing mocap. I'm still figuring this system out, so I can't offer a lot of meaningful information about it. IK Booster is another poorly documented feature, but a good third-party resource are the two video courses by Spline God, one on IK Booster and the other on editing mocap in Lightwave. The presentation in these videos isn't as nice at the RH videos; they're basically a recorded 'webinar' so the audio is difficult to listen to, and the videos could benefit from a lot of editing. But if you're looking for info on IK Booster, it's THE source and there's actually a lot of good information there.

For my current project, I'm still weighing whether I should be using IK Booster or more traditional Lightwave rigging tricks for editing mocap. In the end, it will probably be a combination of the two, plus Animeeple, depending on what we're trying to accomplish in a given shot.

Hope this helps. :)

G.

Richard Hebert
11-26-2010, 12:05 PM
Thanks again for the quick response. IK Booster would be an asset if it worked on the Mac. Right now, it's not possible to undo a pose or bone rotation as the undo feature simply does not work and NT has been informed. Copying and pasting data from one rig to another doesn't work on the Mac version either. But... I really appreciate the info. regarding rigging. I'm going to have to rely on rigging without the benefit of IK Booster for the moment so I'm looking into Rebel Hill's material. Larry's material is superb but not doable at this time. Maybe the upgrade to LW 10 may resolve some of these issues. If not, I'm going to be really upset with the purchase. If your project has a site shoot me a link. Wouldn't mind seeing what others are doing with LW.

Richard

Greenlaw
11-26-2010, 01:53 PM
For my purpose, I mainly see IKB being useful where I have a lot of keyframes baked into an item and I need to change the motion (mocap being the main example.) From what you're saying it sounds like IKB might be working well enough on Mac to at least do that. I'm able to do most of what I need to do without IKB, but from what I've seen IKB should make certain types of mocap editing easier, so it's certainly worth trying (Mac or Win).


If your project has a site shoot me a link. Wouldn't mind seeing what others are doing with LW.

I've been putting together a production log for the project, but it's been coming slow since I'm actually working on the project too. I hope to get a few pages up soon though. For now, you can see the first third of the animatic at www.gothtober.com (http://www.gothtober.com). Just click on the 31st.

You can also follow some of the production on our Little Green Blog. (http://littlegreendog.blogspot.com/)

Enjoy! :)

G.