PDA

View Full Version : Are None Zero Rotation Axis bad to have on a Control?


Zeusbwr
09-25-2007, 05:24 PM
Its obvious that having zeroed controls is best (and manditory in most cases), but are zeroed rotation axes also manditory? Im not seeing any problems now, but i don't want to notice problems down the road during the animation stage.. getting flipping or whatever may happen.

What i am doing is correcting a controls Rotation Axis. It does not match the surrounding controls rotation axes, so when you rotate the group they do not all rotate the same. Correcting this is simple, by just offsetting the parent and then offsetting the child opposite of the parent to zero things out, but none the less this leaves you with none zeroed rotation axis on your main control.

Thoughts?

Global
09-26-2007, 05:02 PM
Zero'd out rotations on a control object would certainly be preferred. Not sure what you mean by the "surrounding controls", or what your exact setup is, but I'd suggest putting in 'null' nodes above the control object. A null is just a transform or 'group' that is a parent of the control. Using this parent node you can move and match whatever rotational axes you need, without changing any of the child's attributes - keeping them zero.

Just come across this recent post which may be useful
http://forums.cgsociety.org/showthread.php?f=88&t=539411

Zeusbwr
09-26-2007, 09:11 PM
Hehe, you didn't even mention rotation axes :argh:

And what i ment by surrounding control objects, is for example, if you have a leg FK system (hip, knee, and foot), and you want to select them all and rotate them to bend the knee and the foot in a kicking pose, you'd expect to just grab one axis and start rotating. Well if their rotation axes are not aligned, one controls X direction might not match another controls X rotation. For example, +X on one control might rotate forward, and +X on a different control might rotate to the left.

Remember, im talking about "Rotation Axis"s. A Rotation Axis is not the Rotation Value, it is the axes in which the rotation values go by.

Here is a mel example:
These are Rotations
setAttr "nurbsCircle1.rotateX" 0;
setAttr "nurbsCircle1.rotateY" 0;
setAttr "nurbsCircle1.rotateZ" 0;
These are Rotation Axes
setAttr "nurbsCircle1.rotateAxisX" 90;
setAttr "nurbsCircle1.rotateAxisY" 90;
setAttr "nurbsCircle1.rotateAxisZ" 90;
(Note that code is not ment to be executed, im just showing the attribute names).


My controls do have zeroed out rotations, but i am asking if having none zeroed "Rotation Axis"s are bad.

And note, i already do use nulls to offset rotations. Ever single control in my rigging setup has 2 parent groups. One is to zero out the control, so it will be matched to whatever you need it to be, then the 2nd group is to offset the 1st, and do not need to rotate&freeze the physical control... which i've found to do odd things, and this is more predictable for me.

Global
09-27-2007, 05:14 PM
Oh right, 'Local Rotation Axis'... sorry I didn't quite get the question. Um... this may not be helpful but as far as I know you won't have any problems. I change LRA's on joints all the time and have yet to come across any probs (On a spine setup for example I'll flip LRA's to make the spine bend in the same direction) Though I've not really done anything like that on actual controls. I'll often rotate the null or parent of the control to match the local rotational space of a joint... but I don't recal changing the LRA of the control itself. I don't see that it would be much of a problem - but I'd wait till you got a second opinion on that ;)

Zeusbwr
09-27-2007, 07:51 PM
Oh right, 'Local Rotation Axis'... sorry I didn't quite get the question. Um... this may not be helpful but as far as I know you won't have any problems. I change LRA's on joints all the time and have yet to come across any probs (On a spine setup for example I'll flip LRA's to make the spine bend in the same direction) Though I've not really done anything like that on actual controls. I'll often rotate the null or parent of the control to match the local rotational space of a joint... but I don't recal changing the LRA of the control itself. I don't see that it would be much of a problem - but I'd wait till you got a second opinion on that ;)

Well it was already in place before i posted, but im building my rig in chunks, and i've got the LRA thing in 2 out of 5 chunks, soon to be 5/5, so im more asking in hopes that if there is a problem, i'll find out before i finish the rig hehe.

Anyway, thanks! Looking forward to hearing 2nd/3rd opinions :)

CGTalk Moderation
09-27-2007, 07:51 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.