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Thread: Another BVH Question

  1. #1
    Old Lightwave guy
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    Another BVH Question

    Hi All,
    I'm seeing that this has been beaten to death but I have questions... and problems. Specifically, regarding this archived thread. I can do all the instructions that Larry has laid out but why do we move the bones around then mess it all up by pasting a motion on top of it which moves all the bones again. Am I missing something here? The only way I can get anything decent from one of the CMU bvh files is to throw it into BVHacker and tweak it to better fit my model.
    It appears that the tutorials on both Kurv and VFXcast are gone from the face of the internet and I haven't found any other video sources for this info. I'm sure you guys have it figured out, any help would be appreciated.

    Thanks,
    Thad

  2. #2
    Eat your peas. Greenlaw's Avatar
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    This may not help you directly but the easiest way to deal with mocap in Lightwave is to retarget the .bvh data to your character in a program that supports mocap retargeting, export an FBX file with the animation, and then transfer the motion data to your character in Lightwave using Load Items From Scene>Merge Only Motion Envelopes.

    In the past this meant using Motion Builder, which is still commonly used, but unless you have access to the educational license, it's very expensive. Luckily, these days there are a few alternatives available.

    A couple of web options are Ikinema Webanimate and Mixamo. The concept is to upload your character, choose or upload your mocap data, retarget and edit, preview online, and if you like the results you pay a fee to download the data. I haven't used either of these services but some users here have. Hopefully, somebody will comment on which system is preferred and why.

    Last year there was a free program called Animeeple, which did a fairly decent job with retargeting. Unfortunately, development stopped and it's no longer available. You might be able to find a copy floating around but I'm not sure if it still works for Lightwave 11's FBX format.

    Blender has mocap retargeting but I've never used it. I think one issue with using Blender will be its limited FBX support. (FBX import or FBX export is missing--I don't remember which one but you need both to do this effectively for use with another 3D program.) I understand that FBX support is being improved so this might become a viable solution for Lightwave in the near future.

    Some entry level mocap systems like iPi DMC and Jimmy|Rig Pro have built-in mocap retargeting.

    We use iPi DMC for our short film productions like 'Happy Box'. We use Motion Builder for our Lightwave retargeting but the native iPi retargeting system is supposed to be quite good and the devs recently made improvements for Lightwave compatibility. I haven't used it but I know a few users have commented positively about this. Here's a demo video from the floor at this week's Siggraph: Siggraph 2012 Day 2. Unfortunately, I don't think you can import existing mocap and retarget in iPi Studio, but I think they are considering this feature.

    Jimmy|Rig Pro supports .lws natively. I don't have much recent experience with this program so hopefully somebody who does will offer more useful info about it. I do know that J|R Pro allows you to import existing mocap and retarget to Lightwave characters. One unique feature is that you don't even need to rig your character--J|R rigs your character for you during import. This may have pros and cons depending on your workflow but I'll leave that for somebody else with more experience to comment on.

    Another possibility is iClone 3D Exchange. iClone is a 'game engine' type of animation system and they recently expanded support for getting your own content in the program through the Exchange program. I haven't used iClone but I believe you can retarget either Kinect based mocap or imported .bvh to your rigged character and if you have at least the 'Pipeline' version of Exchange, you can export an FBX for other programs like Lightwave. (If you have the 'Pro' version, you can only use the retarget for your imported character in iClone.) I'm not sure if you also need the main iClone program to do the retargeting so make sure you read all the requirements--otherwise, it could possibly be an expensive solution.

    Modo recently added retargeting. Their system is based on the Ikinema system. I haven't used this myself yet.

    I think Messiah does .bvh retargeting too or something like it. I haven't used Messiah but I know it can export for Lightwave. (Though, I think these days most Messiah/Lightwave users export .mdd from Messiah rather than keyframed animation.)

    As for native mocap retargeting, Lightwave does not have this yet but it may be coming. This week Newtek unveiled Lightwave 11.5 and Genoma which already seems to go a long way in addressing many of Lightwave's CA shortcomings. It was hinted at Siggraph that they may add Kinect capture support so it wouldn't surprise me if this meant they were also working on native mocap retargeting. This is just speculation on my part though, and you shouldn't expect to see anything before the end of the year at earliest. (Which really isn't that far away I guess.)

    If you do go the Motion Builder route, it's very easy once you understand the basics. The general workflow is to bring your rigged Lightwave character into Motion Builder via FBX, import .bvh, retarget, edit, bake and then export an FBX for Lightwave. Then in Lightwave, open your rigged character, choose Load Items From Scene > Merge Only Motion Envelopes for the Motion Builder FBX, select the character and, voila!, your rigged Lightwave character inherits the motion data from the FBX. Lino actually demonstrates this workflow in the Siggraph video posted yesterday using Genoma, but this works with current 'non-Genoma' mocap rigs too.

    IMO, this is infinitely easier than importing a .bvh file into Lightwave and trying to adapt the .bvh rig to work with your object, especially if you have a lot of shots and characters to work on.

    I know this info doesn't help if you're really committed to using .bvh directly in Lightwave with IK Boost but I thought you'd like to know what the other options are.

    G.

  3. #3
    Super Member SplineGod's Avatar
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    Quote Originally Posted by Thad View Post
    Hi All,
    I'm seeing that this has been beaten to death but I have questions... and problems. Specifically, regarding this archived thread. I can do all the instructions that Larry has laid out but why do we move the bones around then mess it all up by pasting a motion on top of it which moves all the bones again. Am I missing something here? The only way I can get anything decent from one of the CMU bvh files is to throw it into BVHacker and tweak it to better fit my model.
    It appears that the tutorials on both Kurv and VFXcast are gone from the face of the internet and I haven't found any other video sources for this info. I'm sure you guys have it figured out, any help would be appreciated.

    Thanks,
    Thad
    I use the bvh generated bones as a base skeleton because retargetting is a lot easier if the mocap skeleton and your skeleton in your rig are the same.
    I put the bvh generated bones into my character because the bones need to fit it to get proper deformations AND the bones have to be RESTED in order to properly deform the mesh. The Bones REST position and orientation needs to match the pose of the character or vice versa.
    You can use your own custom rig but you run into the motion retargetting problem which is why its easier to use the bvh generated skeleton as your basic bone setup.
    The reason I strip all the motion off the bvh bones initially is to make it easier to get the bones into the character.
    Once you have the character setup with bones you now need a way to get the bvh motions onto it. This can be done in a couple of ways:
    1. Load the bvh file and immediately save it as a scene file.
    Clear the scene and load in your character with bones.
    Use load from scene to load the motions off the scene you just saved onto your character. Since the bones are exactly the same between both scenes the motions should load onto your rig just fine.
    2. Load your character with bones and then import the bvh file. Youll have a bvh skeleton with motion and your character with no motions.
    Apply IKBoost to both characters. Copy the motions from the bvh skeleton to your rig.
    Greenlaws suggestions are also a good way to go as well. In the end I still end up applying IKBoost to the bvh data or fbx data because I find that editing the mocap data is easy to do with IKB. Hope that helps. If you need further help contact me on skype.

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