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SirCharles
07-22-2008, 04:29 PM
I am building a snake rig.
Using splineIK. The rig is 9 joints, with one controls per joint. Each controls is driving a cluster that is driving a CV on the splineIK curve. Then there is a scale attribute that is pumping the current length of the curve usung arclength into the Y on each joint as a multiplier to make it scale with the curve.

There are 2 problems I cant seem to solve.

1) I need a way to twist the splineIK from a per control level. So that when you rotate a control in the middle of the spline it will twist that area of the spline but not the rest.

2) I have a scale control on the rig, but when I move the controls in the middle of the rig the end of the tail doesnt stay pinned with the controls.

Anyone have any ideas or know of any example rigs that have solved these problems?
Thanks

Charles

Boucha
07-24-2008, 12:59 AM
1) I need a way to twist the splineIK from a per control level. So that when you rotate a control in the middle of the spline it will twist that area of the spline but not the rest.

solution - As far as I am concern, Using advance twist option for spline ik will evenly distribute the twisting but will not solve the per control level twist.Use ribbon setup, it will solve the per control twist...

2) I have a scale control on the rig, but when I move the controls in the middle of the rig the end of the tail doesnt stay pinned with the controls.

solution - This is the typical behaviour of spline ik, this can be eliminated into certain extend by creating the ik spline strechy or use ribbon setup...

-Thanks

SirCharles
07-24-2008, 01:03 AM
What is the Ribbon setup? I have never heard of it. (or I heard of it as a different name and therefore dont know what you mean.)

Boucha
07-24-2008, 04:32 AM
Ribbon system is a unique and a bit complex system of riggng technique used for spine, neck, tail, etc with the use for nurb surface and hair follicles that has certain advantages over the typical spline ik setup...

The idea is straight forward...

1. Create a nurbs plane of UV patches 1 and 5 (Depends on no. of binding joints you are using)
2. Create hairs on the nurb surface with UV patch equal to that of nurb surface...
3. We are mainly concern with the follicles only so you can delete other nodes such as hairSystem, curves, etc except for the follicles...(You can also use rivet script)...
4. You can now move the CVs of the nurb surface and immediatly see that the hair follicles follow the surface...
5. This is it, now you can create 5 joints (binfing joints) and parent each one to a respective follicle and zero out there translate channels, now the joints move along the follicle which is attached to the surface.
6. Now you can create some fk joint chain along side the nurb surface and smooth bind the fk joints to the nurb surface...

The idea is that the fk joints deforms the nurb surface which intern controls the bind joint which is parented to the follicle...The bind joint is smooth binded to the actual geometry...

xenoid
07-26-2008, 04:48 AM
Or if you do not have Maya Unlimited,
http://forums.cgsociety.org/showthread.php?f=216&t=442120&page=2&pp=15

This setup is pretty old now but it should give you something to start with.

Boucha
07-26-2008, 11:19 AM
nice work Xenoid, really cool stuff...

Now I am starting to think that maya's hair follicle system may have some connection with pointOnSurfaceInfo as well as closestPointOnSurface nodes.

Great stuff, really helpful...

TimForbes
08-29-2008, 10:39 PM
hi guys. i've found this thread useful in sloving a bunch of rigging issues i was having. cheers for the ribbon joints tute xenoid. I thought you might be interested to see a MEL script that I threw together that automated the ribbon joint setup process.
cheers,
Tim Forbes.

Boucha
08-30-2008, 02:15 AM
Nice work Tim...

But, major issue...you have turned of the scalability of the window...
-s 0
Also, there should be the proper joint placement, joints are a bit offset...
There are no fancy control objects, constraints, etc...

But, overall its pretty good and thanks for sharing...
Cheers!

TimForbes
08-30-2008, 03:24 AM
yeah, my bad. I fixed that just before I posted it, but I must have uploaded the old file. I'll attach the un-locked one now. Cheers for the comments, I reckon i'll refine it but I just quickly threw it together for a rig I am building for this months rigging challenge.
I'll tweak it up a little and post back here soon.
Tim.

xenoid
08-31-2008, 08:07 AM
No problem Tim. Glad that it's useful for you. And nice work on the script. Except for the few points that Boucha made, I think you are good to go with the ribbon rig on Kito. All the best for the challenge! :thumbsup:

TimForbes
09-01-2008, 08:52 AM
cheers, I've started to refine the script a little more and will post back here once it's refined to get some more feedback.
Tim.

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