Querying attributes on a specific frame

[slainye]

Hi! Sorry if this is really obvious but I was just wondering if it was possible to query attributes on an object for a specific frame without having to actually go to that frame in the timeline and then query the attributes, so something a bit like the xform command but with a flag for specifying the frame no. that the attribute is sampled on. Hope that's not too confusing, have tried hunting around in the mel help but not really found anything vaguely relevant apart from currentTime but maybe i've missed something? I would basically like to calculate the speed of an object without the object being a passive rigid body or a particle (as these have velocity attributes which can then be fed thru the mag function) Thanks, Pixelfudge

[denny-lindberg]

[b]getAttr -t 12 pCube1.sx;

[/b]Would return the attribute Scale X on pCube1 on frame 12. I hope this is what you're looking for.

[joojaa]

I would basically like to calculate the speed of an object without the
object being a passive rigid body or a particle

querrying out of context halts mayas dg evaluation so while you can do this wit getAttr -t your paying a very very heavy price or doing so. Fine for one object pure death for lots of them. I would stipulate that if you compound thsi with ALL the associated problems most peopel do when they just use expressions, you negate the entire purpose of using maya in the first place.

instead use a expression to store the last frames value. by making a extra container:

$diff=yourObject.oldValueAttr-yourObject.ValueAttr;
yourObject.oldValueAttr=yourObject.ValueAttr;

Yes this does make it a simulation, but thenagain getAttr -t dont amke for a much more meningfull evaluation as you probably use the information in something that cant be used for direct lookup in anyway.