View Full Version : arms penetrating body during animation...PLEASE HELP!

09 September 2006, 03:11 PM
i have a problem with stopping the arms of my actors ( whom have all been properly mapped w/ mocapped data) from ocassionally just going right thru their midsections (stomachs) and legs during certain movements in their performances. can someone point me in the right direction on what type of constraint need to be applied to prevent this from happening??? or is it not a constraint that i need? is it a rigid body situation? or just somehow consraining the rotation of the elbows? i'd really hate to have to manually go in to the mocapped data and key those penetrating arms out of the body/legs. and if there's any tutorial or someone could referance in the user guide this process please do so. i'm desperate!! and on a tight deadline looming overhead with many character to go! thanks in advance!

09 September 2006, 09:11 PM
Sounds like you might want to take a look at the Character Settings.

In the Navigator where the Character Definiton and Character Settings panes are look down the list in the Character settings you'll see things like reach, offset, pull... sounds like you'll want to adjust the reach settings on at least the elbows and knees. The reach setting effect how your specific characters nodes reach the source node.

You might also want to take a moment and see how all of the other controls in the Character Settings affects how the mocap data works on each of your characters.

Good luck and I hope this helps


09 September 2006, 02:54 AM
thanks for the help and input so far, sammer. i'm gonna give that a shot. for some reason, when the files were handed off to me, it appears the data (actor) generated from the mocap system was then just mapped directly to the character(s)/model(s). so it's just the actor data driving the character (model & skeleton with proper MB bones naming convention exported from LW). there is no actual MB control rig on the character(s). the mocap system is recording directly into MB. so in this case, is characterizing the model, then creating a control rig, then plotting the actor mocap data to the character (motion retargeting) a better way to set up the character for manual keying out of the inter-penetrating limbs if the problem persists? or is the just actor driven character better?

09 September 2006, 09:29 AM
If you have multiple characters and a tight deadline it may save you some time if you check out all that you can do with the an actor under Motion Capture>Actor Assets in the manual.

It would probably be easiest if you started by seeing what happens when you adjust the properties in the Character Settings, you may also want to check out the adjustments you can make in the Actor Controls window.

Good luck


09 September 2006, 03:20 AM
It's not technically the way to do it, but I have gone in to the LW model grabbed the skelegons and the mesh from the shoulder down to the end of the arm. Then rotated (from top of shoulder skelegon) the arms up past the top of their existing T stance by roughly the same amount that the arm penetrates the body. Redo your FBX export and it should be good. You could psoosibly also do the rotate in Layout before you export, but I haven't tried it that way so I can't say for sure.

09 September 2006, 01:16 PM
I do permutation of SoftDistortions method, just all within MB.
I take the characterised model, put them into a TPose, uncharacterise, rotate bones accordingly, re-characterise. It's also a good way to tweak things like twisted feet etc...

09 September 2006, 01:35 PM
I find it's easiest to plot to the control rig, add keys to a new layer where the body parts are intersecting. If you add a zero key at the start and end of the new layer, your actor will resume the original animation.
For example, if his arm intersects at frame 170 and continues until frame 190, set a zero key at frame 165. Add as many keys as necessary to solve the interection issue and then add another zero key around 195 to have the actor resume his original motion.

Layering animation is one of MB's greatest tools.

Art ;)

09 September 2006, 08:28 AM
thanks to you all so very very much for all your help so far! my only problem seems to be this: since the files were handed off to me as: an actor (MB's generic grey human Actor with mocap sensor data mapped to it) directly mapped to and driving the character (LW model and skeleton), there is no control rig and thus no options appearing avail. anywhere to add layers or even keyframes showing up to edit in FCurves. should i just uncharacterize, create a control rig, then replot the actor animations to the control rig to gain access to these features??

09 September 2006, 10:30 AM
you need to plot your actor to the character and then solve your intersect issues by manually keying them, or using the quick hack Colkai and I have suggested.

09 September 2006, 04:01 AM
thanks again for the input. i've tried all the adjustments with little hlp/effect. so i've accepted the fact that i'll have to manually key the intersections out. preferably on a different layer. but i can seem to access and data in the FCurve window. no matter what i select (be it bone/joints on either the driving actor or the character it's mapped to) the FCurve window is empty. how do i acces this data to do the manual keying on another layer? or is keyframes in the FCurve window only visable and editable on actual MB control rigs??? i'm about at the end of my rope and pulling my hair out.

09 September 2006, 08:16 AM
I'd be sorely tempted to plot the current track to a story clip, save that.
Load your character, apply the story clip, then apply an addative character sub-track, it will be much easier. It would also make the action available to any character you choose to use.

09 September 2006, 10:26 PM
...unless you ploted to your chracter all you will have to workwith in a setup like you described - Opticals>Actor>Character- is the optical fcurves which you can use for cleanup etc but won't be useful to do Layers like you want to now do.

Did you try the arm rotation suggesion above? What happened?

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