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 Post subject: Maya best practices?
PostPosted: Fri Dec 03, 2010 4:00 pm 

Joined: Wed Dec 01, 2010 5:26 pm
Posts: 5
I did my first successful mocap yesterday and the results were fantastic despite not having the best working conditions. I'm really impressed with this software so far. However, I hit a stumbling block and I'm hopeful that one of you Maya wizards have blazed a path I can follow :)

My goal is to take the mocap data either as .fbx or .dae or .bvh and import it into Maya and then apply the motion to another character rig. I've tried several approaches to this in Maya 2011 and I get nowhere. The best practice (I believe) is to use the HumanIK tool to basically link the mocap skeleton to the existing rig - but I run into a couple roadblocks:

The imported mocap skeleton has a couple locked attributes like RotateX, etc. They're also keyframed, so when I disconnect them I lose animation data. Also, it looks like the local rotation axes are all different - they don't match the global axis setup, some do but not all - and when I try to Orient Axis I can't do it because they also have rotation applied to them that has to be zero'd - but when I zero that and orient the axis to match the world axis, the animation is all screwed up. If I actually get the mocap skeleton and the character rig linked in HumanIK nothing works, the character actually disappears from the screen, probably because of the local axes orientation problem, or a scale/translate problem.

So - I'm not sure what to do, I'm far from an expert in this. Hopefully there's an easier way to apply this mocap data to a rig. Any ideas?


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 Post subject: Re: Maya best practices?
PostPosted: Sat Dec 04, 2010 7:22 pm 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2346
Location: Los Angeles
I haven't done the following myself but you could try importing your character as a .dae file to iPi DMC and then retarget the mocap data to that rig from within iPi DMC. You can then export the result as a .dae and import it to Maya.

Other options:

You can use Animeepleto retarget to a custom rig via imported .dae or .fbx, and then you can export the character and rig as .fbx or .dae. Be advised that for .fbx export you need to buy a plug-in. By the way, here is what I do when using Animeeple:

1. I import a custom rig and mesh from Lightwave to Animeeple via .fbx. I drop the rig into a scene.
I import an iPi DMC .bvh into the same Animeeple scene. I drop this motion onto the custom rig. The custom rig adopts the motion. While here, I open the animation tab and tweak the 'foot planting' options if necessary. (With my current characters, I have to disable this feature because of their extreme proportions.) I export the result as a new .fbx.

2. Next, I bring the 'iPi-2-Animeeple' .fbx into Lightwave and batch export the motions from the joints in the rig using a script called Multimotion, and then use Multimotion to load the motions to the joints in my custom rig with additional controls and proper weighting.

There are a few 'workaround' details I left out to keep this example simple but that's the basic workflow.

In theory, you should be able to simply import the .fbx or .dae and just go, but this depends on your animation program and how well it reads these formats. I imagine Maya should be able to do this well being an Autodesk product.

And then there is the 'pro' approach, which would be to use Motion Builder to retarget the data to a custom rig and mesh. The data can be then be exported as FBX to your animation program.

Hope this helps.

G.

Edit: I've rewritten part of my 'workflow' desrciption above for clarity.

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Last edited by Greenlaw on Sun Dec 05, 2010 9:48 am, edited 2 times in total.

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 Post subject: Re: Maya best practices?
PostPosted: Sat Dec 04, 2010 9:12 pm 

Joined: Wed Dec 01, 2010 5:26 pm
Posts: 5
Thanks, G.

I spent a couple days trying to retarget the data and I finally resorted to taking the character rig I have, disconnecting the bones, and reattaching the bones from the iPi software. I think the main issue here is that the local joint orientations on the iPi bones are all oriented in different directions and they all have to conform in order to easily retarget. Maybe someone from iPi could comment on this.


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 Post subject: Re: Maya best practices?
PostPosted: Sun Dec 05, 2010 9:55 am 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2346
Location: Los Angeles
znelson wrote:
I spent a couple days trying to retarget the data...

Ugh! I think I know exactly what you're going through. Even though my workflow sounds simple, I actually spent weeks doing trial-and-error testing and sorting out all the details. I'm sorry that the workflow I have is mostly Lightwave specific and probably won't help in Maya.

Hope you get your iPi-to-Maya system worked out soon. And when you do, please post the details! I sometimes use Maya at work, so I'm very interested in your efforts too.

G.

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 Post subject: Re: Maya best practices?
PostPosted: Thu Dec 16, 2010 9:58 pm 

Joined: Wed Dec 01, 2010 5:26 pm
Posts: 5
I ended up taking my character rig (that we bought pre-made) and disconnected the skeleton, and then I matched the iPi skeleton to the original one. I lined-up every joint and bone perfectly and then bound the skin. I thought that would all make sense - just pull out the old skeleton and plop-in the new one with the mocap data on it.

Well - it sorta worked but not 100%. The iPi joints have local rotations on them that don't match the original joints on the rig we bought. So I tried to manually adjust them and that sorta worked but it was sloppy. The legs matched-up OK between the skeletons but the upper body was pivoted back too far so the arms looked all weird - and this is with the skeletons and joints lined-up perfectly between old and new - it's just the local rotation of the joints that causes the problem - I think, I don't know.

So even with the weirdness, I still got a decent result. The character moves just like I did in the mocap session - it blew my mind the first time I saw it. But it took like 8 hours to get the mocap recorded and processed and then another 8 hours to mess around with the character skeletons. I wonder if the processing wouldn't be faster if it had an option to use the cpu's instead of (or in addition to) the gpu. I have a serious 8 core machine but the cpu's are hardly engaged during the processing - they stay around 3% utilization, meanwhile my Radeon 4850 video card must be slammed. I get around 5s per frame, so it's not too bad, but I gotta believe my 8 cores could do it faster. Maybe there's some algorithms on the gpu that would be too difficult to write into code so they don't do it.

Anyway, I gotta find a better way to do this. I don't think the local joint orientations of the iPi skeletons are correct or normalized - I could be wrong but they don't all point in the same axis directions - maybe that's the problem.

On a side note - I really gotta figure out this Animeeple thing. Maybe that tool would allow me to retarget the mocap data easier. I downloaded and played with it but the UI just got in the way - I couldn't figure anything out and chalked it up as a toy. I gotta revisit that.

I bought a license tonight - maybe iPi could comment on their skeleton joint rotations.


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 Post subject: Re: Maya best practices?
PostPosted: Thu Dec 16, 2010 11:00 pm 

Joined: Mon Aug 03, 2009 1:34 pm
Posts: 2346
Location: Los Angeles
Yes, I would recommend at least trying Animeeple. The interface is a little quirky, but once you understand it, it's very easy to use. Oh, and it's currently free, so why not?

I started out trying something along the lines of what you described, but Animeeple has eliminated all that nonsense for me. Hope you can get it to work for you. :)

BTW, (maybe we already discussed this, but I'll bring it up anyway,) you're supposed to be able to retarget within iPi DMC by importing a .dae of your rig and character. Unfortunately for me, .dae export in Lightwave still has a lot of problems so I haven't been able to test this properly. Maybe you could try a .dae from Maya?

I'm using .fbx to move Lightwave data between Lightwave and Animeeple and it works fairly well. Much better than .dae anyway. If iPi can get FBX IO working in iPi DMC soon, that would be awesome. Especially since Lightwave 10's FBX IO is already working so much better than in previous releases.

G.

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 Post subject: Re: Maya best practices?
PostPosted: Sun Dec 19, 2010 11:30 am 

Joined: Fri Dec 10, 2010 9:59 pm
Posts: 3
Here is what I've done for retargeting skeletons in maya. If you have mel experience the steps can be put into a script to make it automatic. Constrain position and orientation from the source root to the target root. Then constrain orientation from each source skeleton joint to the corresponding target skeleton joint. Then select all the target skeleton joints and bake out the keys. Then export the target skeleton into a new file. I must have done this 300 times for a certain cheesy creature flick this past summer, so I made a mel script to automate the process.


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 Post subject: Re: Maya best practices?
PostPosted: Sun Dec 19, 2010 9:19 pm 

Joined: Sun Dec 12, 2010 11:31 pm
Posts: 6
Location: Melbourne
I did a test in Maya 2011 using some BVH data from iPi provided by another forum member. Characterizing the imported skeleton from iPi and re-targeting to a HumanIK rig worked first time. I noticed the joint orientations on the imported skeleton are not consistent but the HumanIK re-targeting system seemed to hand this just fine.

There are a lot of controls in the HumanIK and FBIK system in Maya 2011. Looks like this functionality has come from Motionbuilder?


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 Post subject: Re: Maya best practices?
PostPosted: Mon Dec 27, 2010 8:06 pm 
iPi Soft

Joined: Tue Mar 31, 2009 9:13 pm
Posts: 804
The following video can be useful for Maya 2011 users:

http://www.youtube.com/watch?v=l1hV8BqsCEA


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 Post subject: Re: Maya best practices?
PostPosted: Mon Dec 27, 2010 8:19 pm 

Joined: Wed Dec 01, 2010 5:26 pm
Posts: 5
Thanks, Michael. I followed that exact tutorial but it seems the problem is the joints created by the iPi software aren't normalized. They're pointing in all different directions so it's impossible to match it to the new skeleton created by the Maya HumanIK tool.


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