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barbapapa
10-30-2008, 01:50 PM
hi guys. Im creating a rig where i need to change the pivot point at times depending on the animation. More or less like a skate board rig would be. The problem is that so far im just generating cycle dependencies and the rig becomes really unestable (me and my really basic knowledge on rigging). How would you go about it??

Thanks in advance

McNistor
10-30-2008, 02:44 PM
ctrl+K on the object you want to modifiy its pivot.
you'll find a tab called "pivot" in the window that appears.

barbapapa
10-30-2008, 04:37 PM
Great!!!Thank you very much

McNistor
10-30-2008, 05:56 PM
you are wellcomed!
to avoid cycle dependencies, as a general rule, you should not constrain a parent to its child or an obj_X to an object that is constrained to the obj_X's child (which is an indirect way of constraining a parent to its child = bad).
keep your rigg clean and make sure you have the geomtry into a different branch than the rigg. make your rigg work without needing the geometry and by this, I mean that your rigg should be 100% functional even if you delete the whole geometry (no parenting between rigg parts and geom parts => only constrains or envelope). an alternative way is to parent geometry parts to rigg components but not vice versa => no rigg component should be a child of a geometry part.
I hope these insights will help you doing better future riggs.

NunoNisa
10-30-2008, 07:16 PM
You shouldn't change the pivot at all. That's the last your 'resort' and it should never be touched. Changing the pivot will make your life a lot harder in the long run. Instead you should build multiple layers of controls with zeroed out nulls.

In a skate rig, knowing the center of the borad is the main pivot and the tail the second and the nose the third for example, you would have a null located on each desired pivoting point. Than you should parent the board and each null to the main board null and after you should pose constrain the board to each pivoting null. Animating the blend of the constraints will give you much more control and a much more stable rig than changing the geo pivot.

Finnally you should have a couple more extra nulls on top of everything just for minor animation corrections.

Just be sure of making all the hierarchies (parenting) before you constrain.

I even made a quick test secne for you but it seems that we can't upload different file types than images...damn..

Cheers.

barbapapa
10-31-2008, 10:19 AM
You can attach zip files. And thanks again for all the advice

NunoNisa
11-03-2008, 12:51 AM
Thanks. Check the scene in the zip file then.

Cheers!

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