continuous rotation

[detbear]

Hey everyone.

 

I need a bone to spin more than 360 degrees in an animation. I need it to be able to spin around and around many times.

 

I recall having to switch the bone to Euler for this, but I can't seem to remember how or where to go in order to get that done.

 

Do any of you know where to do this and how????

[Fuchur]

You can find that at "Tools > Options > Action".

 

See you

*Fuchur*

[John Bigboote]

OR- rotate the bone a little to get it's attention... then in it's property window R click on Rotation and select 'Convert Driver to Euler'. It will give you a warning that says you may mess-up any prior rotational keyframing, say OK.

[John Bigboote]

Whats happening is the program wants to rotate from where you keyframe start and end in the least amount of effort... so if you had a clock with the minute hand starting straight-up 12 O'Clock and you wanted it to rotate clock-wise to 12:35, you would Rotate the hand around to 12:35 and when you playback would see that the hand travels COUNTER-clockwise to get to its target. Likewise, if you wanted to animated a full 1 minute and 5 seconds of hand travel, you would rotate the hand 1 full evolution plus the extra 5 minutes- but upon playback the hand would only travel from 12straight-up to 5 seconds! WHY? Because basically- that's what you told it to do. Euler driver allows for the different way of calculating the in-betweens, great for clock hands, auto-wheels etc and you will need to be able to switch between Euler and Quaternion very swiftly.

[Fuchur]

OR- rotate the bone a little to get it's attention... then in it's property window R click on Rotation and select 'Convert Driver to Euler'. It will give you a warning that says you may mess-up any prior rotational keyframing, say OK.

 

Didn't know that was possible... thanks John .

 

See you

*Fuchur*

[detbear]

Hey Guys... Thanks for your feedback on that.

 

After I posted this, I asked about it at Roberts live Q&A. So I had found the answer I was looking for.

 

Main thing I found was that you have to set a key on a bone in order to get the drop down option to "change driver" type to Euler.

[robcat2075]

While we are on rotation methods... has anyone done much with "Vector"? In my few tests with it, it seems to have even less gimbal lock problem than Quaternion, but is there some drawback?

 

 

Here is a test of Quat, Euler and Vector put through the exact same keyframes and Vector appears to do the best interpolation of the three.

 

QuatEulerVector.mov

[detbear]

RC...

 

Hey Big Guy. I don't think I've ever switched to Vector. At times I went with XYZ only, but never Vector.

 

Does that just give you two channels?

[robcat2075]

Vector is four channels, like Quat.

 

Here's the test PRJ

 

Quaternion Euler Demo03.prj

[Xtaz]

I would use an expression GetTime() at the rotate axis....

 

Tranform.Rotate.X=15*GetTime()

 

360º in 1 second ( 24 fps )

[NancyGormezano]

For those that are interested - here is a nice description of Eulers, quats (and perhaps may give insight into Hash Vector implementation). I have not used vector interpolation in A:M.

 

As the article points out, and as I have always known and believed is that gimbal lock is more a problem with using Eulers, rather than quats. This is why we used quaternions, when I was working for Link Flight Simulators (for navigation as well as image generation).

 

However that is not to say that A:M's specific implementation might have a problem with quats and gimbal lock. Not sure why they would. It may be the internal setup of interpolation method?

 

http://www.chrobotics.com/library/understanding-quaternions

 

(I have not checked the accuracy of the above article)

[robcat2075]

Yes, Quaternion is way better than Euler. My test surprised me in showing that there still was a combination of rotations that had any problem.