Awesome Particles Render(Not done by me though)

[ykcosmo]

Peter, you suggest to do something similar to what happens into this thread, but at rendertime, right? sounds very interesting. I didn't thought that you could define a density value for a volume at rendertime.

anamous, could you be a little more precise please? I don't understand how do you use that ray-hit test.. and why you do a ray hit test.

"..ray hit test against a supplied geometry" hem.. what geometry? :\

sometimes......You "can" fake the "density" for a volume at rendertime.....

It might be not "real density", but "looks" similar....

There are some papers about this topic, . one of the paper I read is written by a talent guy in R&H ...can't remember the detail, need to search with google again..-.-!

-.-!

Edited August 10, 2010 by ykcosmo

[pclaes]

Peter, you suggest to do something similar to what happens into this thread, but at rendertime, right? sounds very interesting. I didn't thought that you could define a density value for a volume at rendertime.

One thing is the simulation part, the other just a trick for helping to render shadow approximations (you could actually use a lot of points copied onto). But yes, you can define a density value for a volume at rendertime.

Have a look at the shader in this shop. It needs some filtering, but should show you where to modify the density. You just need to write that pointcloud to disk as the

op:`opfullpath("../../../volume/OUT_PCLOUD")`

expression does not seem to work.

pc_volume_01.hip

[anamous]

Here you go, a simple sample scene (H11). What this does is basically render a polygon geometry as a volume without needing to IsoOffset it first. It renders slower than a simple volume would but the point here is to avoid the IsoOffset step as that can sometimes be very time consuming to impossible. In this case the torus is rendered as a volume, and the cube is just there to illustrate shadowing. The "IsoOffsetting" basically happens at rendertime.

Now, In the context of the original question in this thread, we only need this for the following reason: to use Particle Fluid Surface SOP on a million particles, generating a mesh, which we then use to calculate shadow maps which we can then use at rendertime to create shadows on the particles themselves. And the shadow map generation is pretty fast.

That being said, if you're interested in rendering objects as volumes, you might want to look up the vm_uniformvolume rendering parameter which is new in H11. It basically allows for the same thing but obviously more optimized.

cheers,

Abdel

hackedVolumes.hip