Rigging help needed for spider robot

Support Animation and Rigging
1

I could use a hand here. I am rigging a spider robot and having some difficulties getting an IK rig together that works for the joints.

The basic issue is that I am trying model shoulder type joints as a the combination of a rotator and a hinge. The following URL shows the mesh and the rig I’m trying to do.

http://home.comcast.net/~biggernoise/WIP.html

At first I tried making the Rear pivot (which should only rotate) the top of the IK chain. However, I’m pretty sure that there is no way to say that a given bone is only supposed to rotate about its local Y axis.

So…Enter Plan B.

I changed the RearUpperLimb.r parent to be the same as the pivot (the non-moving bone from the center), I took the pivot out of the IK chain as well and made RearUpperLimb.r the top.

What I want to do is somehow get the pivot to track to the rotation of the upper limb, but nothing I am trying is seeming to work.

I’m honstly about ready to just do the whole thing with FK, ut I thought I’d give it one last whirl before I gave up on IK.

-Andy

BTW - The robot mesh is based off of a recent tutorial in 3D World. Not important to the topic, but I don’t want to pretend it is a totally original creation.

2

I’d like to help, but the images on that webpage links to a local address (d:/…)…

I’ve done such rig as you describe, so I might be able to help you.

Martin

3

Crap. I guess it’s time for me to actually learn how to do this web stuff. OT, know a decent freeware replacement for FrontPage? As you can see, my pages are pretty simple. Perhaps I should just write the HTML.

At any rate, these work.

http://home.comcast.net/~biggernoise/images/SpiderJoints.jpg

http://home.comcast.net/~biggernoise/images/SpiderJointsSkeleton.jpg

If the pictures aren’t clear, I can shoot you the blend file.

-Andy

4

Pretty clear.

You can do that using Lock Track constraint combined with the IK chain. It’s a bit hard to explain, so I’ll try doing an example file latter tonight.

Martin

5

Check this: http://www.clubinfo.bdeb.qc.ca/~theeth/Temp/Leg.blend

Only the main chain is visible, so you’ll need to unhide the bones to see how it works.

Martin

6

Very, very cool. Yes, this does exactly what I want, and I think I can even manage to figure out how it works (I’m on the road this week so time is limited).

Thanks so much,
Andy