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cdmcg
12-14-2008, 03:08 PM
Hello all,
I am rigging a car for a friend of mine and I have ran into a problem. I was working on a SDK to act as a steering wheel and i went to set it up and noticed that the local rotation is off center. Instead rotating on flat planes its tilted at a 45 degree angle. I can post a screen grab if no one understands what I'm saying. What I'm wondering is should i just SDK the two axis it has to rotate on in global to get a flat rotation or is there a way for me to center out the rotation axises.

SeanC
12-14-2008, 08:30 PM
No you shouldn't do the SDKs on two axes.. remember to keep it simple as possible.

assuming you are using maya

What you need to do is put the steering wheel on a normal axis; where the steering wheel faces +Z (or any normal direction, whatever direction you face the wheel, that will be the axis that rotates the wheel) basically so the rotations are what you are looking for and Freeze the Transformations.

then you need to group the wheel to itself and use that group to place the wheel where it needs to be in the car. This will allow you to keep the local rotations of the wheel, but on a 45 degree angle.


hope this helps if not post a screen grab and i'll be able to guide you through it.
:)

cdmcg
12-15-2008, 12:50 AM
Yeah, I didnt think having one sdk drive three rotate channels on one object was good. But here is a screen grab which has the outliner open and i have the group selected that I am using...well would like to use for the sdk rotation. The rotate tool is set to local axis.
Here is a link to picture.
www.cmcgstudios.com/axisIssue.jpg (http://www.cmcgstudios.com/axisIssue.jpg)

I tried freezing trans on the group and every object inside the group and nothing. If i go to global axis it centers it but if i rotate on a flat plane is uses all three axis.

SeanC
12-15-2008, 01:20 PM
okay I think I understand..

from looking at your screen grab, your FLTurnGroup axis is off.. your X axis is fine, but Y and Z are rotated off center. you need either Y or Z to control the action of turning the wheel left or right.
it seems that one of the groups above FLTurnGroup is off center so you need to add a "zeroGroup" that offsets it back to normal..



heres what you need to do:

deselect everything and hit ctrl+g twice.. this should create an null and group the null to itself.

name the group FLZeroTurnGroup and the null will become your new FLTurnGroup

now parent the FLZeroTurnGroup under the FrontLeftWheelGroup

now your FLTurnGroup should have the correct axis to rotate left and right on one single axis.

parent the FLSpinGroup under your new FLTurnGroup and you should be ready to go.

PS: if your FLTurnGroup adopts some funky rotations, before parenting it under the TurnGroup create a ZeroSpinGroup by grouping the FLSpinGroup to itself and parenting the new group under the FLTurnGroup.

this should be new structure:

FrontLeftWheelGroup
-FLZeroTurnGroup (has non zero transformations)
--FLTurnGroup (zero trans) used for turning
---FLZeroSpinGroup (non zero trans)
----FLSpinGroup (zero trans) used for spinning


hope this makes sense, let me know if its still not working and ill help you best i can..

cdmcg
12-15-2008, 02:05 PM
Thank you the double grouper fixed it, i dont know why i forgot about double groupers. Again thanks, much appreciated.

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