Spinning Instances Planes!

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  01 January 2013
Spinning Instances Planes!

Alright, so I am using planes with an image sequence for Arnold renderer happiness. How do I get the planes to point at a moving camera AND rotate around. I can get a little spinning using aimPosition for camera facing and shifting the aimUp value...but it is only a little spinning.
Any thoughts...for some reason I feel like I need to be doing some vector math to set the rotations explicitly...and that scares the be-jesus out of me.
  01 January 2013
Put each plane in its own group. Aim constrain the group to the camera. Then rotate the plane inside the group. That what you're looking to do?
Demo Reel 2012-13!
  01 January 2013
Oh wow, does that work?
I should have clarified that by instances I mean particle instancer instances. My bad...I was in the dynamics forum and assumed...
  01 January 2013
That works for regular objects. As far as particles go, on the instancer section, there is "Aim Position." You can create a new userVectorPP, and for the userVectorPP enter:

userVectorPP = <<camera.tx, camera.ty, camera.tz>>;

Then under "Aim Position" you choose userVectorPP and they will all face the camera. I don't know how to go about rotating them though but maybe this is a good start.
Demo Reel 2012-13!
  01 January 2013
Havent tried it yet but you could use aimUp = <<cos(time), 0 , sin(time)>>; while aimDirection is the camera pos - particle pos as mentioned above.
Sometimes though if this doesnt work, Ive swapped the expressions around and voila. A little bit trial and error.
  01 January 2013
ooh ooh I like the sound of that one.
I will give it a try tomorrow.
Thanks for the tip.
  01 January 2013
Cant seem to spin it on the Y axis, need to look into it more, maybe its gimbal lock. Hopefully you want to spin on X axis. Scene attached.
Attached Files
File Type: zip particleSpin.ma.zip (10.5 KB, 18 views)
  01 January 2013
Oh man that's awesome.
Thanks for the scene...just got sat down to work...it will be a big help.

I was definitely thinking the rotate order setting on the instancer might need to come into play...or I could shift around my instances/rotation axis.

Thanks again~
  01 January 2013

Got into the scene and all is clear.
Thanks so much for the help.
One beer coming your way!
  01 January 2013
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