CGTalk - Spring Rig Help

Sphervotic

03-24-2011, 05:11 AM

Hey there,

I'm currently working on a rig for a set piece on a project I'm currently working on. It involves the said set piece to compress down into a spring and bounce upwards again. I've found a tutorial and have been trying to adapt it's instructions into a test piece I have. This is what I have so far:

Spring Test (http://www.mediafire.com/?3tncc6c9hpbo5e0)

If you select the "springCurve" in the outliner and play around with the scale Y attribute it basically does what I want it to do. The only problem I have now if trying to figure out a way such that when I move the "topCTRL" it replicates the same kind of motion you get when you scale it on the Y-axis. I've played around with the Distance tool and connected the distance to a multiplyDivide node, and then connected it to the scale Y on the springCurve. This has worked to some extent however when I move the "topCTRL" the spring doesn't stay rooted to the ground like I would like and instead breaks it's position and continues to fall through and squash.

Any help offered is much appreciated

Cheers,

Sphervotic

shinyprem

03-24-2011, 08:55 AM

Hi..!
I have' nt seen ur attachment. Having said that I believe its a helical spring. In that case add the bones on the spiral (more no. of joints) add a ikhandle from the top to the tip. moving the ik will give u the compression effect. Maybe will look at ur attachment when I go home.
Rgds,

duld

03-24-2011, 10:39 PM

This isn't the most elegant solution but if I understand you correctly it should give the functionality that you're looking for. I used a simple blendshape and a few set driven keys. If you would like to include a "stretched" state, just sculpt another blendshape using a lattice and remember to delete history on the new object before adding as a blendshape. The same principal applies if you wanted to the spring to have some squash and stretch.

hope this helps

http://www.mediafire.com/?a2q4sqrorob8o7o

Sphervotic

03-29-2011, 01:36 PM

Hey all,

Thanks for the replies, it didn't give me the answer to my problems straight away, but it did help in giving me a few ideas to how to go about it. The completed solution is in the link below

Solved Spring Rig (http://www.mediafire.com/?hmutn0zrna2no0r)

The idea was to combine the wire deformer method and using joints to help maintain position. If you guys have any questions to how I did it, just let me know and I'll answer it to the best of my ability.

Cheers,

Sphervotic

EDIT: As it turns out, you could only squash the rig up and down, you couldn't move it around such that it could squash and stretch upon multiple axis. I fixed this by applying an Aim constraint on the curve to the controller.

Actual Solved Rig (http://www.mediafire.com/?r74otponsh8o50r)

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