Max freezes when creating multiple IK chains

[dean_punchard]

I'm trying to rig some cables using IK chains and the HD Solver.

However when I create more than one, Max will freeze. One CPU will be maxed out. But nothing happens.

It will sometimes work in a clean scene, but not on this product I'm working on.

The bones I'm rigging aren't connected or linked to anything else in the scene.

I also can't save the cables to another file, rig, and merge back in, as this also causes Max to freeze.

Copying the IK chain doesn't work either, as it will freeze when I re-assign the bones in the IK chain.

I'm using Max 2024, all up to date. 

This also happens in Max 2026.

Any ideas?

[leeminardi]

Can you give more deails about what you are trying to rig?  Perhaps IK HI solvers could be used instead of the compute intensve HD solvers.

[dean_punchard]

It's basically a toilet seat aid, so the seat lifts. It's a really simple rig, just a piston pushing the back of the seat up so it pivots on the front. This is linked to a master dummy to re-position the seat.

There are power cables connecting the control unit to the pistons. These bend and adapt when the seat moves. I'm just trying to rig it so it's not all manually keyframed, which I could do, but I thought this was a good time to try IK in this situation.

I'll try HI solver and see if this gives the effect I'm after. I could also look at rigging it with TyFlow, but felt like that was overkill, when the tests I've done with IK, bones and Spline IK modifier (to link the spline to the bones) seem to give me everything I needed for this, and future products.

[leeminardi]

The rigging of the  piston pushing the back of the seat up is a simpe 4-bar linkage that can be easily done with an HI solver.

As for the cable movement I would consider fudging the action  by using a Spline IK Control modifier on the cables.   YOu may not need bones for the rigging.

Post a picture, or better yet a Max file, and you'll get more detailed suggestions.

[dean_punchard]

Yea I can try the HI solver for the piston, and the Spline IK control for the cables.

Is it pretty common for HD solver to freeze Max then? Is it that intensive? I'm guessing it's not multithreaded either?

[leeminardi]

My experience with IK HD solvers is very limited and am hesitant to comment about their perfromance.  Since the calculations are cumalitive they are only good for, as I understand it, short animations so I have avoided using them.  I have written my own solvers for special applications.