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eagle4
05-09-2006, 10:35 AM
hey guys, i am doing a snowboard animation, i have set up a reaction on my characters spine so that i only have to move the base of the spine and they all bend nicely to give a nice curved back. now i can move this from sie to side as well as forwards and backwards. now my problem occurs when i have got him flying through the air and i set him to do a grab. which is no problems, then just after the frame where he does the grab the animation goes all screwed. there is 1 frame where his spine apears to be turned completely arround then the next frame its back again. so after HEAPS of mucking arround i got rid of it on the frames where it was occuring, now i have an even worse problem, the pop in my animation is occuring BETWEEN frames, i can see this by looking at my curve editor. when i togle backwards and forwards on the time slider i cannot see this pop, but when i hit play you definately see this pop.

can anyone please explain what may be causing this to happen? and if you know how, is there any way i can fix it and any way i can prevent it from happening again.

my teacher's 3d expertiese is with Maya not max so he dosnt know how to fix it. he says it may be Gimble Lock.

or if you can tell me a better way to rig a spine so that it bends nicely without having to set up reactions

please help


eagle4

PEN
05-09-2006, 12:32 PM
It does sound like gimble lock but without seeing it I couldn't tell you for sure. How is the spine rigged?

eagle4
05-09-2006, 12:46 PM
the spine is set up only with reactions, the master is the bottom bone in the spine (there are 4 bones in the spine in total)

i set it up with reactions so that i only rorate the base one and the others all have their own rotations so to give a nice bend if that makes any sence. i have set up the reactions for the rotation in all 3 directions. so if my character leans to the side he bends nicely, if he bends forwards or backwards his back looks good, and if he twists there is a progressive twist happening throughout his spine.

is there any way to cure this Gimble lock in Max?

or is there a better way to rig the spine?

eagle4

virtualmesh
05-09-2006, 07:54 PM
If you're experiencing gimble lock then try changing the axis order on the first bone located within your bone-chain that spins out of control. usually with a spinal column, you can get away with having the 90 degree rule being on either the L/R twist or side/side rotational axis. Usually a forward/back bend exceeds 90 degrees so I would not set it on that axis.

I assume that you have a rotation list controller holding multiple Euler XYZ controllers for each bone that is in your spinal chain.

eek
05-10-2006, 12:53 AM
the spine is set up only with reactions, the master is the bottom bone in the spine (there are 4 bones in the spine in total)

i set it up with reactions so that i only rorate the base one and the others all have their own rotations so to give a nice bend if that makes any sence. i have set up the reactions for the rotation in all 3 directions. so if my character leans to the side he bends nicely, if he bends forwards or backwards his back looks good, and if he twists there is a progressive twist happening throughout his spine.

is there any way to cure this Gimble lock in Max?

or is there a better way to rig the spine?

eagle4

Theres no really way to cure gimbal in any package - it happens in the real world. You can only 'soften' its affects. This sounds like your hiting -1 i.e gimbal. Try adding another parent to the mix, and key fixing for a few frames.

Personally i dont use reactions to control rotations. What about wireparam, of even simply instance the controller up the chain and add a float list?

eek

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