Linking problems with Live Character

[Frank Verberne]

Hi all,

I'm encountering a strange problem with linking the mainview to a bone of an animated avatar.

Whenever I use an avatar that's being animated by the Live Character's plugin for MotionBuilder and I link viz.MainView to one of it's bones ('bip01 Head') with the viz.link() function, the result is a choppy mainview. When I link an object ('box.wrl') to the same bone (without linking the mainview to any bone), the avatar seems to be moving smoothly (or the choppyness is only noticeable when the mainview is linked to one of the bones).

The framerate is not a problem, and the stream rate in MotionBuilder (Live Characters plugin) is stable and high enough (set it to 250). However, it seems that the avatar is not updated fast enough when the mainview is linked to one of it's bones (the framerate doesn't drop, but the whole scene is choppy). I already tried adjusting the streamrate of the Live Character plugin, but that didn't help. I also tried linking the mainview to other bones or to use an other avatar, but the problems still exists.

How can I let the headbone move smoothly with the plugin and at the same time link viz.MainView to it?

For the record, I want participants to be able to literally see through the eyes of an animated avatar (they animate it themselves). I'm also working on another solution by linking the mainview to a sensor and then pretranslate that link to just before the eyes. However, that solution is not flawless, and the link-function would be the perfect solution if only the view wasn't choppy.

The code below causes the problem:

import viz
import vizmocap

viz.go( viz.HMD | viz.FULLSCREEN | viz.STEREO )
gallery = viz.add('gallery.ive')
avatar = viz.add('vcc_male.cfg')
lc1 = vizmocap.LiveCharacter('192.168.2.103',8050,model=avatar)
viz.eyeheight(0)
bone = avatar.getBone('Bip01 Head')
viz.link(bone, viz.MainView)