View Full Version : IK Motion Bake to keys problem

08-07-2007, 04:15 AM
(Sorry for the crosspost- getting a bit pushed for time!!)

Exhausted knowledge now. Tired and (common language voluntarily deleted) off. :thumbsdow

I've got a number of IK based anims which Im baking down for game use.
BUT, one has me stumped.

I've got the left hand IK goal parented in this case to another moving item. Using the Dstorm normally reliable BakeIKToKeys plugin to bake this down now fails and I get a hand that drifts, no longer staying in constant contact with the item it is supposed to.

I realise this is probably down to the order LW evaluates stuff prior to baking, but I've still not found a solution.

I've TRIED constraining a null to the IK goal, so I can bake the motion to that, then copy it over, but with little success. The orient constrain worked and baked properly, but the point constrain worked, but then baked wrongly.

I need to be able to reliably bake out the motion of the IK goal to world space, so I can remove it from the heirarchy it currently sits in, OR find a way to use the D-storm plugin with the right results.

Any ideas??
Rob (mailto:[email protected])

08-07-2007, 07:17 AM
can't you make an mdd ? (cloth dynamics, no parameter changes, save motion)
then load it in using the md plug

08-07-2007, 08:11 AM
I'm not familiar with using MDD's, but isn't that point displacement? Not practical within our game engine I'm afraid. Our engine reads LW scene files directly, but doesn't support IK. Hence having to bake the anim down to bones-only.

Thanks for your suggestion though- any more takers?

08-07-2007, 09:01 AM
Use LWs Motion Baker Plugin on that arm.
You can bake an object as an mdd file then use editfx to extract motion from any point.
If possible you also might try parenting the object to the characters hand instead of the other way around.

08-07-2007, 09:17 AM
Thanks Larry,
Using Motion baker on what I've got doesn't work- just gives floaty unconnected motion. I've been solidly dissapointed with it so far- probably because there doesn't appear to be any way to get it to bake after IK

As for the MDD approach; it sounds a bit of a fudge but I'll certainly give it a go. How would I then transfer that motion back onto my rig?

I could always do the other way round approach with the hand. That actually sounds like the most practical approach. I'll just need to remake the anim and probably a few tweaks.

Kinda a shame though because using constraints, dynamic parenting and well, just being able to plonk IK goals elsewhere in another heirarchy opens up a world of opportunity for us, IF we can bake these motions down to the base rig reliably. Some hope for 9.5???? Or maybe some kind soul at D-Storm could look into it for the next version of their so far very reliable BakeIKToKeys plugin.

08-07-2007, 02:27 PM
Bake the bones that have IK applied in that arm first using motion baker.