aim contraints without rotation?

[jAQUAN]

no one knows how to make an aim constraint that will only point without revolving? Is the secret using an orient constraint instead?

[seven6ty]

I'm not really understanding what you're asking. Is it that the sword is rotating along it's axis in a manner you don't want? Is it point constrained to the hand or what? I don't think you've given us enough info about your set up or what it is that you want to change. I'm kind of in the dark, but yeah, an orient constrain would keep it from rotating.

[jAQUAN]

Thanks for replying. I try to keep things simple as I tend to over-explain in my posts :D
I was hoping my movie would better explain it but it's a 2meg download so I can understand if no one bothered.

Anyway, I'm using 4 locators. One on the hip, one for the hilt while sheethed, one on the tip, and one in the left hand. The sheethed hilt and left hand locators are for point constraints. The tip and hip loc's are for aim constraints. As soon as the the blade is completely out of the sheeth, I switch it to aim at the tip loc which is parented to the hand. While turning the sword upright the sword will pivot on its aim axis and as the sword reaches "straight up" it will flip 180 on its aim axis.

Hope I didn't bore you :).

[seven6ty]

Hrmmm, I dunno, still sounds a bit over complicated. Could you not just create a switch (like an IK/FK switch) on the wrist control that would let you turn on and off point and orient constraints for the sword, switching between being constrained to the wrist control and the hip???

You'd actually have to point and orient constrain an null group node, and then parent the sword to that with an offset, so it sits in the hand instead of on the control.

And yah, it was difficult to see what was going on in your vid as it was very jumpy and not very smooth, seemed more like keyframes. But yah, that's more the approach I'd try taking myself. But it's sounding like you'd need an orient constraint to keep it oriented the correct way.

[jAQUAN]

yeah I made the movie by blending single frame clips (not poses) in the trax editor. I didn't edit curves on any of the blends so its choppy.

Basicallly the FK/IK style switch is what I have now. I switch the point contstraint to pass position control from the hip to the hand. I switch the aim constraint so it will quit pointing to the hip.

Where would I add the null group node, to the sword or a locator? Which node would be constrained to what?

I was just following a tut so if there is a simpler method please enlighten me.

[seven6ty]

The sword would be parented underneath the null group node. But you could use a locator also. Try posting up a link to the tutorial here too!

[jAQUAN]

Its the first video listed here.
http://www.gnomononline.com/tutorial.php?category_id=7

I'll try the null nodes tonight. Thanks a lot.

[jAQUAN]

group nodes! brilliant! I just did an orient contraint on the Y channel only, then grouped the sword and aim contrained it to the same locator. And to think, all throughout this rigging book I learned about these but never thought of using them on anything but joints. Thanks so much!

EDIT: Still a little flippy but I think I can fix it enough for what I'm doing.

[seven6ty]

Hahaha, good to hear!

[jAQUAN]

Ok had a little break through. I got rid of the aim contraint for the un-sheathed mode and used only a point and an orient. I have to rework some clips but it is working very well. :)

[seven6ty]

Yeah, I think it's the aim constraint that was messing you up probably. I was trying to figure out exactly how you were using that in there and was never completely sure. Aren't those things fun though??? Hahaha, I use a ton of point and orient constraints with rigging, so I've gotten to know them pretty damned well by now.

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