Bone rotation limits and initial conditions.

Genete · Post by **Genete** » Mon Feb 05, 2007 5:38 pm

Hi,
It seems that I only post tips and techniques... I must apply them someday...

This new one is regarding to the constrained bones.
If you rotate a slave bone by the rotation of a master one, perhaps you want the slave bone to rotate only when the master is in a range of angle.
It is very easy to do. For example let's have tree bones.

master
slave1
slave2

Let's constraint slave1 to:
a) Angle control bone set to master and its value 1.
b) Angle min/max set to min=45 and max=135

Let's constraint slave2 to:
a) Angle control bone set to master and its value 1.
b) Angle min/max set to min=225 and max=315

Now, and this is the important thing, at frame 0 and using the Rotate Bone tool set the initial angle to both bones to 0 degrees.
When you put the cursor to frame 1 both bones take a different position according to their constraints lmits.
slave1 is 45 degrees at frame 1 and slave2 is at 225 degrees at frame 1,

Now manipulate master bone. And see that slave 1 only rotates with the master between 45 and 135 and slave2 rotates only when master is between 225 and 315.

So with this initial conditions you can control two bones with a sigle master bone. It is limited by max min values but think that really there is no limit there. You can put one of the limits set to a very big positive value angle (or negative). Then that limit dissapears and bone is only restricted to a direction on rotation.

I think it is an interesting thing because you can composite diferent movements depending in which angle the master bone is.
For example if one slave bone controls a rotation and other controls a traslation of a bone (perhaps by transrotate script by Rasheed in script forum or by the springy mechanism by me in this forum) You can make angled curvilinear translations of slave bones only using a master rotation bone.

See an example.

http://amanoalzada.iespana.es/partial_rotation.html

Hope it helps you opening new animation worlds.

Regards
Genete

heyvern · Post by **heyvern** » Mon Feb 05, 2007 6:17 pm

You must stop reading my mind!!!!!

Just now I discovered this exact thing!!!

I was playing with a hand/finger rig and used "offset" constraints the way you described so that the index finger controls all the other fingers but by different amounts. Easy finger curls for simple hand animation.

You could do a cool curly tail or tentacle with this too.

-vern

Genete · Post by **Genete** » Mon Feb 05, 2007 6:27 pm

Hehehe
This idea was surrounding my mind several days ago,,,

Since I posted the definitive 3D eye with my 190 bones I have not stopped thinking about how in the hell can I put a realistic 3D eyelid... I need this kind of constraints initial conditions to do that.
I cannot show you more by now because it is under development now, but sure that when I have it i'll share it.
You will be bouncing on your chair!!!

best
Genete

PS: Hmmm tentacles, curly tails.. hehe more uses than I can ever imagined...really we are having a real brainstorming. I don't know if other are following our posts, but they are very interesting....

PS2: One more thing. Ofcourse the angle areas of every slave bone can overlap...

ulrik · Post by **ulrik** » Mon Feb 05, 2007 9:46 pm

He, he oh yes I'm following your posts and I guess others do too, at least I'm trying to follow...ehh, sometimes it's far over my head but at least I understand that you're all developing something very interesting and useful and I thank you for that! Maybe I'll dive in to it and will understand it a bit more later