Camera Billboard - Rotate only around Y Axis

[blaxxun]

Hi guys,

I have a pointcloud with tree billboards instanced in ICE.
Now i want that the tree billboards always face the camera BUT the billboards should ONLY rotate around the Y axis.

At the moment they also follow the camera when i move over or under the ground surface height.

How can i "lock" X and Z axis?

I tryd to modify without sucess: Billboard Orientation, Align Particle to Position, Align Particle to camera.

Thanks!

[rray]

Hi there

You can copy the Rotate Toward Target compound from the "Turret constraint" compound and use it to modify the particle orientation.

[blaxxun]

Okay, i tryd that but "Rotate Toward Target" seems to be a "per object" compound.
I try to modify it from "Pose" to "Rotation" since this is "per point".

[rray]

Yes exactly, this should work (Particle Orientation->SRT to Matrix->Pose). This should make the compound work in per point mode.

[rray]

had a try, was some fiddling around to find out what axis to rotate around, and what is the axis that "aims"

Couldn't get the Pose Out to work, the connection always stayed black. No idea why, I just got the orientation directly out of the compound.

[blaxxun]

Wow, nice! Thanks!

I had to rotate my trees(Y is up) around X by -90 degrees because they where flat on the ground.
Im sure there is an easyier, more clean way to do that, but for now it works just fine.

Vielen Dank!

[dwigfor]

You should be able to simplify the RotToEuler to EulerToRotation. I don't have XSI open, but I think you can multiply your RotateTowardTarget rotation (input1) with a EulerToRotation (set to -90 X) (input2). One of the few times that the order you multiply matters! RotA*RotB doesn't equal RotB*RotA. You always want parent * child.

[blaxxun]

Thats actually what i did, or how do you mean that ?
Could you show it ?

[dwigfor]

Should be same result, just a little cleaner code...

ICE_Tree_Billboards.png

[dwigfor]

My apiologies, it's Child * Parent. Order matters. Sorry bout that!