View Full Version : emit orientation to normal and face to camera?

09 September 2006, 12:11 AM
Leaves on a tree

Need to emit a piece of geometry a leaf growning on a branch using a particle system to emit from a surface thats easy, but my leaves need to grow from the root and align around the tube shape (they don't they all face wacked directions) and I would love if I could keep them facing to cam.
Any ideas out there?


09 September 2006, 01:02 AM
Here's a little PFlow trick:

You can override certain channels of an operator with other operators. So, if you want your instanced geometry to face the camera, you can use a ShapeFacing above the ShapeInstance. What this does is set the rotation and shape channel, but when it hits the ShapeInstance, the shape channel is overwritten. What you (should) get is instanced geo that behaves like ShapeFacing.

05 May 2007, 08:01 PM
Hi guys.

Brandon, your reply answers the "facing problem" but doesn't address the "align to normal problem."

In addition, I'd really like to pin a few hundred vine leaves to the trunk of a tree and have the tips of the leaves conform to gravity/wind etc, is this possible?

Many thanks


05 May 2007, 01:23 AM
There's a hack way to orient particles to a the surface they're emitted from and that's to give them a SpeedBySurface in the direction of the surface normals and a Rotation set to Speed Space. Then with an Age Test set to 1 (Event Duration), you move them to another event that stops them. This snaps them to facing away from the surface normals. You'd probably want to use Instanced Geometry in this case, cards with a pivot point at one end and sufficient polygon detail to deform (if that's what you want). The hard part is deforming the tips. You could fake it by adding a Noise modifier to the instanced geo source and have the effect fade to the root via soft-selection. This could get really slow though.

Hmm, you could do some pretty cool leaves with Box #3 by applying a field based noise to the rotation of fixed particles.

05 May 2007, 12:17 PM
Brandon you're an absolute star!

I tried playing around with speed/rotation to see if I could find a hack. Obviously not looking in the right place.

Thanks again.

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05 May 2007, 12:17 PM
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