7 replies to this topic

[jim c]

I'm trying to instance a bunch of point lights (around 300 in total). I'm noticing that the render has slowed to a crawl. Turning off shadows helps a lot, but it still horrible slow. Is this to be expected given the number of lights, or is it an indicator that I've done something else wrong?

I've got the attenuation set to Physical, the active radius turned on, and set to 1. The light intensity is 0.005. I've got a shot from the IPR so you can see the general idea I'm going for.

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[jim c]

Well now I feel a little silly - forget to mention that I had SSS turned on for the instanced "rib" like shapes. Turning that off sped things up, maybe I can just live with out it.

[jim c]

Interesting, just changing the render type from micropoly to PBR, and PBR wipes the floor with mp. Any ideas why I would get such a massive speedup?

[pbowmar]

SSS can be sped up radically, but you have to dig into the Mantra Surface and find the SSS nodes, and turn on Optimize Secondary Rays. Why this isn't exposed by default continues to baffle me

Cheers,

peter B

[moondeer]

i made it a habit of optimizing 2ndary rays everytime i use SSS. to help here are a few pics.

also, i've noticed that using true displacements with SSS can be rough as well. Lastly, since you've dug your way into the VOP depths, have a look at the presets. (pic 6 attached here).

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Edited by moondeer, 02 June 2012 - 10:12 PM.

[Jason]

Another optimization (if you haven't done this already): set the "Active Radius" on the light you're instancing. It looks like the radii of illumination don't overlap all that much.

[jim c]

Thanks guys. Jason, active range was one of the first things I stumbled on. Peter & Moondeer, thanks, I'll look into this.

[jim c]

Here's a shot of a test - PBR, sampling way too low, but renders in a jiffy. The light is from a "flashlight" and the floor lights that are starting to turn on.

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