mechanical robot rig issues


I’m trying to rig a simple mechanical robot but this is my first attempt rigging something so I have some issues.
I don’t want the lower part ( the red one) to be moved up or down when I move the IK chain. I want it to get stucked on place when I move the IK and the robot gets rotated (all parts except the bottom part).
Maybe the attached image can clarify my trouble.

Thanks in advance.



Put a dummy at the end point, have everything linked back to the base object, select the dummy at the end and use the IK HD solver, and click the base object to set the IK.
Then select each section and go to the Heirarchy tab, select IK at the very top (next to Pivot), then scroll down to the section Rotational Joints, here you can set active which axis can rotate, so set the axis you want to rotate to Active and uncheck the others. So for something like the base that you would likely want to rotate only on the Z axis then you would only set Z to active. You can also set angle limits so that they don’t bend beyond a certain point.


Thank you for your reply but i’m really new to this so I haven’t fixed the problem yet…there are some parts I don’t understand…maybe this is too advanced for me :P.
When you say put a dummy at the end point, do you mean I should link the dummy to the end point?
And when you say I should select the dummy and use the IK HD solver, do you mean I first should link the dummy to the IK solver?

I’m really confused now so if there is a quick fix for this problem and someone kind on the forum are willing to help me I could send you the .max-file :). That would be very appreciated!


Yes, create a dummy, link it to the end of the arm (the last joint on the arm), select the dummy and go to the Animation menu at the top>IK Solvers>HD Solver
That will then put you in the mode to create the IK chain, so select the other end of the chain(the base object) and that will complete the IK, you can then grab either end and it’ll bend things correctly, after that follow what I said earlier about limiting the rotation of the axis for the joints.