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View Full Version : Pflow, mesher and point cache


floopyb
11-19-2007, 06:47 AM
Ok I have a tonne of rocks on the ground, a deflector passes over them and then wind etc starts to blow them around.
I am using a mesher and a point cache on top to remove the Pflow stuff in my render file, because it was crashing a lot! So im just rendering a editable mesh with a point cache on top.
The problem is that when the rocks go into the next event the actual geometry (vert numbers and faces) swap around all over the place! The rocks movemt is fine but as the number of particles in the event is changing the geometry is being recaculated based on this!

This is not playing well with vray motion blur (or image motion blur, I would expect!)
Any ideas on ways around this?

Bobo
11-19-2007, 07:18 AM
Ok I have a tonne of rocks on the ground, a deflector passes over them and then wind etc starts to blow them around.
I am using a mesher and a point cache on top to remove the Pflow stuff in my render file, because it was crashing a lot! So im just rendering a editable mesh with a point cache on top.
The problem is that when the rocks go into the next event the actual geometry (vert numbers and faces) swap around all over the place! The rocks movemt is fine but as the number of particles in the event is changing the geometry is being recaculated based on this!

This is not playing well with vray motion blur (or image motion blur, I would expect!)
Any ideas on ways around this?

There is no good way around this that I know of - the mesh sent to the mesher is based on the combined pool of particles, which on itself is the particle containers of all events combined. So when a particle changes its event, it potentially changes its place in the total list of particles and it causes a topology change.

Before you continue with Mesher, have you tried switching the Render Operator to Multiple Meshes? It tends to solve memory-related crashes with PFlow because by default, all particles are combined into a single mesh and depending on their count, the renderer might become unhappy. Splitting to multiple meshes reduces the number of polygons in each mesh sent to the renderer, while avoiding the need for Mesher and PCache.

If that does not help, then you might have to find a way not to send particles out (things like scripting and Box #3 could help mimic tests by writing flags to channels to enable one effect or another without actually moving particles between events.

floopyb
11-19-2007, 07:36 AM
Thanks for the help Bobo, I think ill end up just putting all the patricles to the next event on one frame then dealing with the bad fram in post. Too much set up work to undo now unfortunatley.
I'll keep your sugggestions in mind for next time though!
Cheers.

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