What's the biggest rendering factor in this smoke scene, time-wise

[urlGrey]

Hello all!

My work occasionally uses Houdini, so I've been trying really hard to learn the ins and outs this past year.

I have a scene, here, that contains a large and fairly detailed smoke simulation. It starts out rendering quickly enough, but soon slows to the speed of a frozen snail glued to the bottom of a large brick.

I've looked at several posts here and elsewhere on rendering smoke, and I have a general idea of what could be taking so long, I guess, but I thought it'd be wise to post my scene file and ask a kind soul to glance at it. Is it just the size and detail of the simulation that slows it so much? Some render setting? Both, equally? :shrug:

The only difference between what I was rendering and the version I'm posting is the inputs and outputs (cache, render, etc) are deleted, and I also deleted what little geometry it had. The emitter is in a strange place because the camera move (deleted from the version I posted) and geometry were imported from another application.

My computer is very fast, but if I should be more specific in that area just let me know.

Thanks very much in advance.

Grey

smoke.hipnc.hip

[Marc]

Rendering is slow, or simulating is slow? If rendering, which would be a good frame to look at for the slowness?

M

[urlGrey]

Hey Marc,

I actually cached the simulation to disk as a bgeo.gz via the dop i/o, so that wasn't really a problem (directly, anyway, that I know of). The render started somewhat quickly, even, but by the early 100's (frame 120, say), it started taking an inordinately long time per frame. The kind of inordinate that's 45-55 minutes.

Now that I've done some more investigating, I'm beginning to think the problem is somehow computer-resource related, or something similarly mysterious to me. I just jumped to frame 150 in the version I posted, only intending to check and answer your second question, and it took less than or around 10 minutes. The only difference is the lack of geometry, that I doubt mattered at all, and the camera... hmmm

Oh, but that was just in the render view, by the way, not saved as a tiff to disk like the original was--which was 1920x1080.

Edited May 21, 2013 by urlGrey

[3__]

don't have houdini on me,

(wonder if batch will run on a debian-based phone...)

but it seems like you're running into a memory-leak that gets worse with each frame.

also raytracing shadows through volumes kills...

[urlGrey]

I'm using ray tracing to render, but depth maps for shadows.

Earlier I was kind of wrong--it went quicker just because of resolution and reduced pixel samples.