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Point + Orient or Parent


#1

I’m an Softimage user fairly new to rigging in Maya. I’ve been working in Maya for years but not much in rigging, and I’ve seen that a lot of times the Point + Orient constrain combo is very used, instead of just Parent Constrain.

I’ve seen that Parent Constrain is faster than Point+Orient so I’m not sure why this is used.

This time I need to use a weighted character with joints, I can’t change it’s rotation values so I’m connecting it’s joints to the mGear rig through parent constrain with offset. Should I change it to Point + Orient ? So far I haven’t seen any issues, but I haven’t tested it with a full animation yet.

Thanks


#2

Hi myara,

A Parent Constraint is not the same as Point+Orient. If the constraining object and targets have the same position, then coincidentally, they will be the same. But if there is an offset, the result is not the same.

This is true in XSI as well. (RIP Softimage. :cry:)

constraints

Furthermore, sometimes you’ll want to control the offset of a pointConstraint or orientConstraint individually. A parentConstraint does not have any convenient offset attributes. (eh… as far as I know…)

In terms of speed, what is your method for measuring that? I can’t imagine there is a meaningful difference. I’ve tested thousands of nodes to compare the frame rate between parentConstraints and matrix constraints, mGear’s matrix constraint, and direct hierarchy, and the differences were pretty small. I don’t think a few (or a few dozen) constraints would make a huge difference.

If parentConstraints work for you, use them! There is no need to switch just because. In fact, there are plenty of bad rigs out there, so usually nothing will ever beat your own tests and observations.


#3

Thanks for the explanation, I’ll have to do some more tests to understand it better.

In Softimage we don’t have a parent or point constrain that works exactly like Maya. I just use Pose Constrain and forget about it. My best solution, so far, to imitate this is using parent and scale.

About the performance, I didn’t test it by myself, but I read it in this blog (japanese)

It says:
Test scripted with 2 constrained locators 1000 times
Empty Scene : 1049.1 fps
Point+Orient : 147.6 fps
Parent : 165.1 fps

Not really a big difference, but I was wondering what was the point in using this combo if the performance is slightly worse.

Thanks


#4

Another reason would be if you want to do blending or switches between only orientation, or only position. Like doing a head orientation switch, where the head aims to the world. But you still want it to stick to the neck in position.