So I have a person on a wheelchair following a path.  I have a dummy object set up for all of the chair and biped components to link to.  That dummy object is given a path constraint (to an animated path) and works perfectly on its own.  Each wheel has a dummy object for wheel rotation, the dummy is then linked to the wheelchair—this also works perfectly.  I have a dummy object (IK object) for each hand of the biped so that the hands can either be attached to the wheel dummy or hold another object (e.g. a door handle) by using a link constraint.  I can link one of the hand dummies to the wheel dummy and everything works fine.  However, if I link the left hand dummy to the left wheel dummy and the right hand dummy to the right wheel dummy at the same time, my computer comes to an almost complete standstill (measured by animation standards it’s well less than a frame every couple of seconds) and in unusable until I remove one of the hand dummy links.

I have tried this on multiple computers and get the same result each time.  If only one hand dummy (either left or right) is linked, everything works fine, it’s only with both linked that it’s a problem.  I tried seeing if it was due to using a Link Constraint instead of just linking, but it’s not—the problem persists. This all happens with a wireframe display, so textures and lighting are not a factor.

Is there something I’m doing wrong? Perhaps I can allocate more memory to run 3DS Max?

At this point, my only solution is to work with one hand dummy at a time and keep track of which frames the dummy is linked to each object.  Then unlink it and use the other hand.  Immediately before rendering, I can enable both links, but I have not idea what that will do to my rendering time if the entire program is running so slowly to begin with. Help!

Thank you.

Check your processors, my guess is they are going full tilt so adding more ram will not help.

There must be some sort of dependency issue that is causing the slow down. What happens when you remove the path constraint and retain the link constraints?

You should post this sort of question in the rigging forum next time.

Paul Neale
PEN Productions Inc.
penproductions.ca / paulneale.com
Master Classes for Max, Mudbox and Composite
DotNet Tutorials

MX Driver Car and Trailer Rig On Sale!

Sorry about posting this in the wrong section initially, thanks for moving it.

The rig works perfectly when the main controller does not have a path constraint.  I’ve used it multiple times, just trying to estimate a path, but that still makes it look like it’s sliding at times.  I just realized the other day that I could actually animate the path itself—perfect for moving a wheelchair back and forth for maneuvering purposes.

I initially just attached my working rig to an object with the path constraint.  This caused the slowdown.  So I went through and attached each object individually to see where the problem lay (First the controller to the path, then the chair to the controller, the biped to the controller, etc.).  Everything continues to work perfectly until the moment I attach the second hand controller.  It’s not a matter of left or right or attachment order (as far as I can tell).

What’s weird is that attempting this causes such a dramatic slowdown, whereas there is almost no noticeable slowdown occurs when one hand controller is attached.  I’d understand if it showed signs of slowing the moment the first hand controller is linked, but it doesn’t!

EDIT: I just tested it using a spline that is not animated, and it works fine. so it’s not the rig, it’s not the constraints - but a combination of everything I’m trying to do. GAH!

Okay, I found a solution that works for my situation:

I have the chair moving forward -> backward -> forward.  So I cloned the spline 3 times and removed the keyframes for each one so that it appears to be one long path.  I then attach the chair controller to each path and animate the path weights so that it is 100% spline1 going forward, then transitions to 100% spline2 by the time the controller starts moving backwards, etc.

By leaving the Path percentage the same as when the path was animated, I didn’t have to make any further changes.

I’m guessing that the spline is the issue, what max version is this in?

Paul Neale
PEN Productions Inc.
penproductions.ca / paulneale.com
Master Classes for Max, Mudbox and Composite
DotNet Tutorials

MX Driver Car and Trailer Rig On Sale!