render times

[dynaman]

guys,

 

i'm pretty new to vray and crash coursing myself into this thing. for the most parts loving the results, but some things are frustrating.

 

i know this is a VERY general question, but i'm wondering what kind of typical render times people are able to achieve. i just finished a small retail interior, fairly complex lighting - 50+ spotlights, some glowing tubes, area light at glazing. with medium quality setting for IM, a 4000x3000 render took 15 hours. no glossy traced reflections.

by lowering quality settings, i was able to produce 640x480 previews in about 6 minutes.

do these times seem reasonable?

 

and what's the deal with glossy reflections? even with minimal usage, it kills my render times.

 

i should mention that i am using an AMD dual core 2.2Ghz, 2GB ram.

 

if anyone has any tricks to speed things up without losing quality, i'd love to know...

[Arnold Sher]

you are running a decent machine and your render times do not seem that bad, however here is couple of tips that should speed things up:

 

-use photometric lights

-do not use raytracing shadows, use shadow map

-use vray materials

 

that should speed your rendering times dramatically... Please let us know how it goes

[dynaman]

thanks for that! when i first started checking out vray, i thought i'd read somewhere that it didn't support shadow maps, so i haven't been using them at all. i'm sure that alone will make a huge difference (especially in the case of 50+ spotlights!!)

i will also have to test out the photometrics. this is one that i have heard mixed opinions on. some have said that they slow down render times.

i have already made the switch to vray materials. definitely makes it run better (if not only faster).

[sorin maximilian]

I'm new as well but I have an idea

50+ lights?

the number of lights has a significant impact over rendering times anyway!

if you let them all to be part of GI calculation you just make it even worse.

Maybe you did that already or maybe you should give it a try: exclude most of the lights from GI, you can leave them casting shadows (vray shadows, map shadows) if you really need them all.

In the end that's the beauty of GI, it can generate a perfect lighting solution out of 1-3 key lights. You seldom need more than that.

And stay out of any raytracing! refelctions, shadows, materials forget them!

Hope is not too late, hope it was helpful.

take care

[skogskalle]

use "store with IRR-map" option on all your Vray lights. You will have to use higher settings for your IRR-map (since the quality of those lights now depends on the quality of your GI) and this will take longer than before, but the actual render will be much much faster.

[dynaman]

great suggestions! thanks guys - i will give them all a try. and if i notice any big differences i'll let you know.

[dynaman]

sorin,

how do you exclude certain lights from the GI? i searched around in vray properties, object properties, and within the light itself, but couldn't find any kind of toggle?

thanks!

[Thablanch]

Some statements in this thread that I can not agree with:

 

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you are running a decent machine and your render times do not seem that bad, however here is couple of tips that should speed things up:

 

-use photometric lights

-----

 

This is true and false at the same time, most of the files that you can download on the web will actually give better looking result as what the light beam should be, but increase render times like crazy, to complex file info I guess..

On the other hand, if you do generate yourself a simple curve .ies file yourself using pies.exe or the other soft. That I can not recall the name, render times should be quite fast. As a standard max light with attenuation is the simpliest light, should be the fastest light.

 

-----

 

use "store with IRR-map" option on all your Vray lights.

 

-----

 

Actually, that is probably not what he wants here..

If he do use spotlights, he is not using Vray lights (or else that would really kill rendertimes)

the "store IRR-map" option basicly makes the light shooting a first bounce instead of direct light, so there is NO direct light anymore!!! If he uses spotlight, what he is trying to acheive is theses nice pseudo-crisp vray shadows. I'm not saying it is not faster, it is faster most of the cases, that's probably just not appropriate in this situation.

 

The store IRR-map option is quite well describe in this Flipside tutorial, mid page:

 

http://www.aversis.be/extra_tutorials/vray_studio_lighting_02.htm

 

On that, my notes:

 

If you really need reflections on your vray materials, use the option Use lightcache for glossies, that should make the reflections way faster, like 3 times faster.

You could also play with the material interpolation in itself to get faster results.

But of course, no reflections is the fastest way to go

 

But as everybody stated already, 50 lights is a lot, so simple lights, as much as possible, you could try get down the Vray shadow subdiv. in each of theses lights. In a spotlight situation, you can sometime afford to go as low as 3 and still get some decent result. ( of course, when your general lighting coming from the windows is doing most of the job!)

[Crazy Homeless Guy]

how many subdivisions are you using on your glossy reflections? ...try lowering them, and use the interpolate option to make keep them from being noisy.

[dynaman]

thanks for all the feedback!

 

in response to some of the suggestions:

 

"store with IRR map"

- i have found that this setting does help a lot in scenes where i am using a majority of vray lights. it's most useful because i can get away with running a vrmap at lower resolution, then loading it into the final production render. also allows me to make slight changes to the direct light sources, materials and non-GI creating objects and quickly re-render (much quicker!!)

- true that in the scene with many max spotlights this wouldn't have made a huge difference

 

IES lights

- i was surprised at this suggestion because i have read elsewhere that this can actually cause a major increase in render times. as mentioned by thablanch, i guess it all depends on how well you know how to control them. for me i think sticking with standard lights is easier at this stage

 

glossy reflections

- i do avoid these wherever possible, and i have found that you can achieve pretty decent results by (within the material) disabling reflection, and unlinking the highlight glossiness and tweaking.

- i will have to do further experimenting with light cache because i have found it to be slower than QMC in every situation. i must be missing something

- interpolation is helpful, but can be a pain in the ass with the extra pre-passes, especially when you disable glossies for quick previews (still does the extra pre-passes). shouldn't there be a global on / off switch for interpolation??

 

shadows

- shadow maps do seem to work well - great tip

- i will also try lowering subdivs on my spotlights with vray shadows

 

exclude from GI

- still haven't figured out how to do this. can anyone elaborate?

 

 

i have already learned a ton with help from here and through experimentation. thanks so much! keep 'em coming! i will post a couple of images when i'm through my current crunch.