volume procedural octree divisions and lost details

[mrWolf]

hi all volume procedural lovers,

I have a volume procedural shader that generates clouds from points. I was thinking to use this to create a large cloud distribution at render time (I've a 'twin' variant of the same shader that creates the same volume in sop using bounding boxes to inspect specific areas of the distribution, so I can preview the result quickly).

 

I realized that when the point distribution I use as an input becomes very large, in my renders I loose all the details. I tried to crank up the parameter "octree division" up to values that make the pre-processing stage immensely long, and still I am very far from the details I have if I use a way way smaller point distribution. 

 

My question is:

since the volume procedural shader is able to render "gridless" volumes, this should allow rendering pretty much infinite volume distribution. Or ... to be more precise, this is what I (naively) thought !

 

Is there something crucial I am missing in my setup, or the only solution is split my data to countless small partitions, and pretty much nullify the advantage of the gridless volume render ?

Edited January 27, 2015 by mrWolf

[jkunz07]

Have you tried increasing the volume quality parameter on your mantra rop?  This determines the step size as a ray marches through the volume.

[mrWolf]

I made a quick test at home and it seems to work !

If I couple this with Octree Dubdivision ~128 it renders relatively fast too.

I'll try it tomorrow at the office.

Thank you a lot for this suggestion Kunz !