View Full Version : HyperVoxels, Motion Blur, and render times

03-20-2006, 10:15 PM
Okay so I have a fairly simple scene. Couple of emitters, couple of collission objects, the main subject, and some debris. I am making an explosion, so one of those HV emitters ends up filling a huge amount of the screen. My rendertimes are pretty huge (well, okay theyre not that bad at all... just huge for the time limits im working in)--i think i did one at about 6 hrs. Not sure if that was full resoltion or not, but it was with less-than-satisfactory AA passes.

Anyhoo, I'm looking ways to cut down on the times, and it seems to me that using the motion blur post process filter and dithered motion blur yields good results with less passes. Problem is, the filter doesnt affect the volumetrics. Is there anything at all i can do to either make the motion blur filter work for the volumentrics, or reduce the render time enough so that I can use more passes?

I have already bumped down my ray recursion limit to like, 2, since there are no reflections or refractions, and I only have 2 distant lights in the scene.

thanks in advance,

03-20-2006, 10:31 PM
You could render the volumetrics by them self so you could blur them in a compositing program or you could try it in Aura.

03-20-2006, 10:43 PM
hmm i kinda dont have Aura. The only thing other than LW i can think of that I have that may be able to do an explosion is Apple Motion, but I cant get that to look real enough.

well i tohught about post processing the blur, but then, how do I do that without XY motion vectors. Im pretty sure those dont recognize volumetrics... i'll check it out though, thanks

03-21-2006, 12:22 AM
Less particles will obviously help, so try and cut down on them...
Tweak surface settings in Viper.

You could try and use Waverfilter Image Filter....
It has a Blur that can be set to affect surfaces or objects.
I imagine though it would also fail on volumetrics, unsure on that..

There is a motion modifier vector output plugin somewhere for post blur.
again unsure it will help.

03-21-2006, 07:04 AM
Actually, sometimes more particles, but each one smaller, will render faster. Also, if you do find a compositing solution, you can render out at half resolution, expand the image & add some small blur and the result is usually the same, especially for animated scenes.

03-21-2006, 01:54 PM
thanks for the tips guys. I'll have to check out that wavefilter thing... if push comes to shove, i'll probably end up doing what DMarkwick said.

03-22-2006, 12:48 AM
I think sprites are usually used over volumetric HV, in productions like Firefly.

If you want to stick with Volume you can also try lowering the render quality, shadow quality and reduce the number of lights affecting the HV.

There the new plugin, Dynamite, that was free last I saw - it's a little bit faster than LW's HV.

03-22-2006, 07:59 PM
actually I'm using surface... hmm

yeah id love to use Dynamite but--afaik the Mac version isnt available yet :cry:

any links/tuts/tips on how to do explosions with Sprites? All the stuff ive seen is either volume or surface...

03-22-2006, 09:29 PM
Using surface? For little chunks or something? If you can substitute geometry for that it'll fly.

I don't know of any tutorials, but sprites are similar to volumetrics but they're 2d -

And Dynamite doesn't do surface or sprites anyway.

03-23-2006, 12:42 AM
heh... nah, I actually just neglected to switch it to volumetric, and tweaked it till it looked ok. (and kept wondering why it didnt look volumetric! gah what a fool!!)

I tried using a massively displaced/subdivided sphere but it didnt look nearly as good.

Anyway thanx for the tips, I'll look into that