Hi everyone !
It is the first time I attempt to rig anything… and I’m encountering quite a little problem.
basically from the picture you can see what I want to do :
The red crosses show points where my geometry should be fix and rotate around. So the idea is that the piston expands/contracts and drags the big “tibia” box and so the “leg” bends.
Lower I have another fixed pivot point were the “ankle” can rotate.

I know exactly how everything should move… but I just can’t make it work that way :p
I have tried using link constraint between the tibia box and the tube that’s keeping it in place, but when I do so, it makes the object I put the constraint on disappear and when I still go ahead without my piece that disapeared, it still doesn’t quite stick to the tibia box as I wish…

Anyway, to make it simple : I’m stuck !

So if anyone can suggest a way for me to do this and make it work… that would be totally AWESOME !

Thanks in advance guys :D

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Try using “Dummy” objects and look at constraints. Link the geometry to the dummy(s).

I always use dummies because then it is easy to switch out the geometry with new and not have to reanimate it.

This file should get it done...2010 version
Of course you have to limit the rotation and motion. I prefer to do this with sliders of one kind or another. Again, control the dummies not the geometry. Dummy001 rotation for the set and dummy002 for the piston link.

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

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link.zip

Oh thank you very much for this, it’s already helping a lot ! And indeed, I should use dummies, it makes everything much clearer !

Now I might be asking too much but… this works fine as an FK structure, but what if I want to implement an IK structures (this is only the leg of a more complicated robot, and I will animate it later, so IK structure would make my animation process much easier).
I have tried to figure it out this past hour or so, but apparently I’m really not that clever when it comes to rigging. No matter what I do something is going wrong…
Best I could come up with is something like this :

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link01.zip

Yeah, it is also the piston that is causing me problems, but I kind of liked it…
And I could just create some other design for my leg without a piston, but now I would like to learn how to solve that problem instead of just avoiding it :p

So thanks for you helps so far, if I can’t find another solution, I’ll do it your way :)
And if anyone else knows another way to do it, it is more than welcomed !

Some links to piston rigging threads:-
http://area.autodesk.com/forum/t18453
http://area.autodesk.com/forum/t35686
http://area.autodesk.com/forum/t541