IR/LM Long Render Times

[jujubee]

I have huge render times for something I didn't think would take that long. I'm rendering at 3333x2500 (in case I want print resolution.) It's an Irradiance Map/Lightmap combo. I set it to render on the network overnight and woke up with a couple specks the next morning. If this is the way it's going to render a large scene, then I was better off just using a traditional combo. Can someone please point me to what I'm doing wrong?

Here are my settings:

[deneb26]

hi jujubee,

what irrmap settings do you have?
IMO the global subdivs is set too high. i prefer to let it @ 1 and just pump
up the sudivs of the local sudiv-parameteres (i.e. glossy subdivs a.s.o.)
this lets you have more control.
let's say you have a glossy material for the floor (for an interior). you give it a subdiv of 1. for the final calculation it's multiplicated with the global one. in your case 16. but maybe 5 would be enough for this mat. so the render-times are way too high in consideration to the desired result.
imagine when almost all of your mats use glossies. they will always be set on a minimum of 16, although it might be not necessary.

greez
ale

[percydaman]

agreed. personally I only go lower then 1.0 when I want to do test renders, then bump it back to one and adjust other settings specifically. Though Im far from an expert on the global subdivs spinner. Until recently, I didn't even know you could go above 1.0...lol

[vlado]

jujubee, did the render go past the lightmap at all? If no - do you have any pure white/red/green/blue materials, GI multipliers greater than 1.0, or output maps in the diffuse slot of materials? Are there any materials with opacity less than 100% or with an opacity map?

Best regards,
Vlado

[jujubee]

what irrmap settings do you have?

Oops. Thought I had included that. -5/-3 with 30/15. May just bring 30 back down to 15.

IMO the global subdivs is set too high. i prefer to let it @ 1 and just pump
up the sudivs of the local sudiv-parameteres

Thanks! It's starting to make sense now.

did the render go past the lightmap at all? If no - do you have any pure white/red/green/blue materials, GI multipliers greater than 1.0, or output maps in the diffuse slot of materials?

Nope. Didn't even get past one tick of the LM but I could see my network lights still going crazy this morning. I do have a pure white background in the Max environment. I'm not sure what you mean to encompass by GI multipliers, but I do have a HDRI mult. at 2. Both color mappings at 1.3 cause the scene was very dark. No output mats in the diffuse slot.

Thanks again for all your help. I'm going to try all of your recommendations and see how it goes. Will keep you posted.

[jujubee]

Global Subdivs Multiplier doesn't seem to be making any difference even at 1.

I do have some glass materials - vraymats with subdivs at 8 in refraction. Relfect is at 3.

[jujubee]

Well, now that I'm further investigating- there's alot of glass polys in the scene as well as reflective materials. I think it's just painfully slow at these settings and I will actually have to lower the subdivs (lower than for all the mats a bit and see if that helps.

[jujubee]

Well- all that didn't seem to make any difference whatsoever. Still hangs in IR/LM mode.

If I run it through LM/QMC on Natty's speed settings I can get through the scene really fast. On IR/QMC it moves along (slowly but surely.) On IR/LM (even after poly reduction, sample downsizing, checking mats, and reducing subdivs) the renderer just dies - not even a tick. Do you suppose it has something to do with this render size?

If you want, I can send anybody who requests it a copy of the scene. I was trying to avoid posting it.

[natty]

I havent read the whole post but how much memory have you got ? and have you got enough?

[jujubee]

2 gigs

[natty]

mmm ... plenty
can you share your scene dude ..

[jujubee]

Greatly appreciated Natty. Now that I've posted my scene to the gallery here's the IR/LM setup files. I've stripped out most of the textures.

Download the IR/LM problem scene here. (2.36mb)

A comparably-sized HDRI (Vol. 3 Sample) can be currently found at:
http://www.sachform.de/download_EN.html

Oh btw, my final image was rendered with IR/QMC with no problems.

[timmatron]

1000 subdivs. on lightmap is usually way too high. Start with 250 and see how that goes.

[jujubee]

Hey Tim- I dropped it down to 250 and managed one tick after about 15 minutes- it was painfully slow (slower than what I'd imagine lightmaps to be.)

[timmatron]

Geez that is slow, even for pretty large scenes. And I believe lightmaps are resolution independant, so it shouldn't even matter if you are rendering at 300 or 3000.

Maybe nows the time that you post your scene for others to take a crack at?