It's all about pointclouds and deforming geometry.

I hoped it'd be easy to create a consistent point cloud with non changing nr of points using pcwrite, but there arouse some obvious problems.

When shading quality is set to 0, no dicing happens (as I understand it) and pcwrite creates one point per primitive.

It is not very useful with coarse unclean geometry.

When shading quality is >0 mantra creates more micropolys and pcwrite creates more points, but adaptively, so they flicker and change nr and all that mess.

Is there a possibility to force mantra (pcwrite) to create arbitrary pc denser than a point per primitive?
In other words to dice non adaptively?

I know I can create pc using scatter SOP and bind point to geometry but … there are other thingies there.

hehe, Just spotted “advanced dicing control” in houdini help .

EDIT : I've set “uniform measuring” and “measure scale” to 10 but it didn't helped much.

Perhaps pc count changing from frame to frame isn't a big thing
and pcfilter copes with such things well :? ?
Could you guys elaborate a bit on this subject?
Is it common to use pc's on animated geometry?

Hi Peliosis,

It sounds like you need to create a rest Measurement for your geometry. If you isolate a single frame of your geometry you can use this with the Measure SOP. This will create a Area attribute for each primitive on your model.

This information can then be copied back to the animated Geometry (assuming consitent point count) With the Rest Area on the Geometry set the Scatter SOP to Not scatter based on Primitive Area, and instead give you're own custum Rest Area.


Heh, it's a bit of a divergence than what you're up to, but should offer an alternative to the poping….

cheers,
-j

A quick note on generating pointclouds during render: try to use the raytracer instead of the micropoly engine, it will give much more evenly distributed points.

Hm, sounds like Uniform Dicing should work :\
Perhaps try Binary Splitting and zero Z-Importance?

eetu.

Sorry to be late for dinner.

Thank you for all the info!
eetu, it seems like I it resolved my problem!

I was sure I checked all parameters but as it appeared…I hAven't.
Now I can fully control micropolys and pointcloud.
Should be nice for low precision non flickering attribute cache for tons of unconnected geo


Peter