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atzfratz
12-10-2002, 01:03 PM
Hi guys.
I have a confusing problem. I somehow messed up my rotation axis. At least i think. After testing it on diffrent workstations i am no longer sure if its a bug, a known problem or normal??!!!

I stepped over it as i was refining some rotation values in the graph editor but the values behaved really strange. So i tested some things and thats what i found out. I will try to attach some pictures to make it more clear.
1. I created a polycube moved it away from the origin to see both, the global axis as well as the local rotation axis.

2.Tool Settings are on Local and i start rotating the cube on the Y-axis. Everything is still fine :)

3.But if i click on the rotate Z Value the axis shown is the global Z-axis.

4.So after rotating this Axis you see that the Rotate-Z-Channel is connected to the Global Z-Axis

5.X-Axis still behaves right as the Local-X-axis and the channel is local too.

6.So when i click on the Rotation Tool again or press "e" again i get back the lcoal rotation axis for Z, BUT when i rotate the object every 3 channels change.

Thats really strange, im totally confused if this is common or something like a bug. Im using maya for quite some time since release 3 but i never realised that problem. I mean if rotate it 90 degrees around the Y-axis, the Z and X Rotate rings match up. No matter what channel i change the object rotates the same way. I dont think that this should happen, or?! What about a car tire i rotate to make a right curve and i cant use the Z-Axis anymore to roll the tire. I mean the graph editor is useless when i have to change all 3 channels to rotate around the local-Z-Rotation axis. I know i could group it, rotate around Y and the Rotate Z of the child, but i simply dont know why the rotate Z channel is not connected to the local axis, as Y and X are.Sorry i didnt tried forum search but i exspected too much hits with "rotation" :)
Maybe some of you could try that on your maya and tell me what happens, just needs a few seconds. Or maybe someone of you can tell me a reason why this is so strange. Thx in advance.
atzfratz
12-10-2002, 01:04 PM
No.2
atzfratz
12-10-2002, 01:09 PM
No.3
atzfratz
12-10-2002, 01:10 PM
No.4
atzfratz
12-10-2002, 01:11 PM
No.5
atzfratz
12-10-2002, 01:12 PM
and last but not least No.6
SamDav
12-10-2002, 02:12 PM
Hi! I don’t know what’s wrong with your scene but there is definitely something wrong. With Maya 4 I replicated what you said and at step 3 I still get the local rotation axis for Z.
atzfratz
12-10-2002, 02:46 PM
Thx you tried it first.
Hmmm, did you actually press on the Channel like you wanna copy it or change the value with middle mouse button ?

I tried that in maya 4 and 4.5 on 4 diffrent maschines and always the same. Well after reading some info from the maya help i found out that you can change the messed up rotation axis by changing the rotation order. Seems like there is a dependecy between the location rings. But if i change the order there is still one channel that messes up. I cant find a reason why the 3rd ring does not rotate like the other two. It seems like the channels in the channelbox behave like the gimbal tool, but i want them to be local :)
any help?

Well and its not only this scene, its in every scene i create on all machines.
SamDav
12-10-2002, 03:15 PM
The infamous gimbal lock problem is something else. It’s when your rotation is locked in the gimbal rotation and it doesn’t happen in local rotation. I clicked on the blue circle with left mouse.

There is something strange happening between step 2 and 3 and you are not clear in your writing. Are you actually saying that when you click on the blue circle in step 2, it suddenly transforms into the blue circle in step 3?
atzfratz
12-10-2002, 03:29 PM
no, actually um clicking on the RotateZ Channel in the Channelbox. So that its highlighted as you can see in the channelbox. After clicking on it it changes to the active and yellow circle, but instead of a local ring i have the global. hoping i explained myself better this time. i just click on what is dark grey in the picture. Local ring comes back when i hit "e" or press on rotate tool or stuff like that. Its just wierd that the value in the channelbox for Z is Global, while it is local for X and Y.
SamDav
12-10-2002, 04:18 PM
OK, Now I understand better. I know what is your problem. It’s not that Y and X are local and Z global.

When you use your channel box and middle mouse button, you are rotating in gimbal mode. That’s why you think it’s behaving strangely but it is behaving correctly.

1) In gimbal mode and xyz order, when you rotate z, (x and y) rotate too.
2) When you rotate y, (x) rotates and z is fixed.
3) When you rotate x, (z and y) are fixed.

That’s gimbal behavior!
atzfratz
12-10-2002, 06:59 PM
yes, after i tried some stuff i think its clear. Its just so funny i never noticed the limitations of Eular Rotations. i found an intresting homepage about that stuff:

http://www.anticz.com/eularqua.htm

You can change the keys in preferences to be quat and the the other keys change in dependency to the others. real strange stuff, but it seems to avoid values above 180 , to avoid flipping for bones and stuff i guess. Even my boss never noticed that problem and he started of with Power Animtor 7 or so. thx for your help. I guess rotation in all 3 axis is not often needed and you can easily avoid the problem if you group your node. Its just that i didn't understand the whole problem, why the Z axis is locked to the global axis but the page above helped me a lot.
bye atzfratz
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