Scene optimisation tips

General questions about Indigo, the scene format, rendering etc...
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dcm
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Scene optimisation tips

Post by dcm » Tue Mar 23, 2010 2:53 am

As topic`s name said, would be great to have some tips and tricks for scene optimisation here. I was searching forum for some, but i wasnt sucessful. Try to write here ur own tricks or tutors how to for example :

1. how to reduce fireflies
2. how to reduce render times (without exit portals) mostly in interiors ?
3. how to use mlt / bidir
etc etc

My big problem now is sun and fireflies. Im doing interiors mostly and i think, sun is "overbrighted" or dunno how to say. When sun is emitting outside of my interior, light in exterior is too strong and light inside is very poor. I tried to play with camera,layers etc but cant achieve nice and soft shadows/sun.

Im using ghostglass for windows and i have fireflies in every scene. Sun layer needs up to 48hrs to render on overclocked i7!!!. Its imho a lot. Sky layer is clean after 4-5 hours. Using Bidir,,,

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CTZn
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Re: Scene optimisation tips

Post by CTZn » Tue Mar 23, 2010 5:21 pm

1. how to reduce fireflies

- use MLT alone (Baygon style)

or

- use supersampling (2+)

There was something about pixel art but let's forget about this :mrgreen:

Fireflies are because only one in n sky samples will hit the sun, can't tell the probability but it's very low obviously. In this regard MLT is much more flexible because it "sprays" samples out instead of picking them one by one.


2. how to reduce render times (without exit portals) mostly in interiors ?

You bet it's all about hacks and tricks... let's see... perhaps set albedos saturation and value alltogether below 0.6 and tonemap (hack) ? add faint emiters along hidden places to fill the space with extra light (and samples. Hack btw) ? What's wrong about exit portals ? they can have any shape so you can wrap (or just cover) a terrace or something outside, still this will prevent light to hit the back of the building (trick finally).


3. how to use mlt / bidir

Because all scenes are different there is no definitive answer to this.

You can evaluate each mode separately for your scene, say for a fixed time. If it seems to you that one mode has an unusually low efficiency then disable it or it will impair the other. If there is not so much discrepancy then they can run together.

Generally speaking, bidir is more efficient under a direct lighting situation (studio, exterior). MLT is known to be more efficient for complex paths: glasses and complex medium, along with indirect lighting situations and among them daily interiors, because only the sunlight patches are direct lighting.

Okay, that's what I can say, hope this helps and waiting for more.
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dcm
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Re: Scene optimisation tips

Post by dcm » Tue Mar 23, 2010 7:54 pm

Thank you citizen! :) This thread seem to be very informative no only for me.

I tried MLT alone and it seem, that sun is more natural and light in interior is more sensitive ( MLT :?: :idea: )
What about MNoCR? Im not sure what i can do with this parameter. Same with BVH. Where and when i can tweak these params ? Next think is sampler. Im using default splat and dwnsize. But what about if i want sharpen output?For example like mitchel or catmul?Prolly i need to tweak splat filter to mn_cubic. Correct me if im wrong.

Im not able to use exitportals due to background planes im using with enivorment texture so i need to wait more or made "thinks behind windows" in postpro.

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Re: Scene optimisation tips

Post by Zom-B » Wed Mar 24, 2010 1:56 am

Some more classic Tips:

Don't use material color higher than 205 in R, G or B (80%)
This isn't only about "white walls" but also applies to any albedo color.
Also Textures are often breaking this by having to bright values!
A to high brightness is unrealistic and let the light bounce way to long so render time raises.


Use pure black diffuse material for emitters with low polycount
This ensures the fastest way light gets distributed over the scene. The pure black
material prevents that the emitter also reflects light, so for bigger emitters this may speed up rendertime!
For Objects like TV or Computer Screens it may be more realistic to have a dark grey phong,
but for simple light meshes that aren't relevant for the scene (besides of emitting light!) this helps!
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CTZn
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Re: Scene optimisation tips

Post by CTZn » Wed Mar 24, 2010 5:31 am

What about MNoCR? Im not sure what i can do with this parameter.
Ideally, nothing :) Touching this parameter can lead to pictural onanism, and by the way induce bias by pruning the most subtle lighting in your renders.

The higher the better since we want Indigo to be accurate if I'm correct ;) Personally I boosted both MNCR and max_depth factory settings x10 permanently.

Q: What happens when you prune subtle ligthing ?
R: Amongst other things:
  • - Rooms corners are darker
    - caustics might disappear
    - enough on bias already !
Don't use material color higher than 205 in R, G or B (80%)
This is totally correct, but in the same fashion let's insist on saturation again ;) H is free, S & V must be under control.
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PowStudios
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Re: Scene optimisation tips

Post by PowStudios » Wed Mar 24, 2010 5:47 am

CTZn wrote: The higher the better since we want Indigo to be accurate if I'm correct ;) Personally I boosted both MNCR and max_depth factory settings x10 permanently.
Really 10.000,- MNCR? Where can I raise max_depth? Is it possible in Blendigo or do I have to modify some preference- or scene-file?

Thanks,
Pow
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My MacBook 'whines': http://www.google.com/search?q=macbook+whine
If anyone has a solution that works pls message!

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Re: Scene optimisation tips

Post by dougal2 » Wed Mar 24, 2010 6:49 am

PowStudios wrote:
CTZn wrote: The higher the better since we want Indigo to be accurate if I'm correct ;) Personally I boosted both MNCR and max_depth factory settings x10 permanently.
Really 10.000,- MNCR? Where can I raise max_depth? Is it possible in Blendigo or do I have to modify some preference- or scene-file?

Thanks,
Pow
You can change MNCR under Renderer tab -> Advanced. max_depth is not exposed in the exporter because usually there is very little reason to change it.
However, I think Indigo has a default configuration file where you can change it (inifile.xml).
Last edited by dougal2 on Wed Mar 24, 2010 7:07 am, edited 1 time in total.

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CTZn
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Re: Scene optimisation tips

Post by CTZn » Wed Mar 24, 2010 7:03 am

PowStudios wrote:
CTZn wrote: The higher the better since we want Indigo to be accurate if I'm correct ;) Personally I boosted both MNCR and max_depth factory settings x10 permanently.
Really 10.000,- MNCR? Where can I raise max_depth? Is it possible in Blendigo or do I have to modify some preference- or scene-file?
Okay, to be honest I lost this habit some times ago :) but it should not impair quality. Beware though, pumping MNCR up has also drawbacks: rare sample paths might not be supported enough by peers and look odd density-wise.
I'd rather not mention the how publicly because we do not want users to spread biased renders by lack of control (it's a very advanced parameter). Actually I must refer to my superiors regarding public policy on those items, please hold on dcm !
Scratch this, good job dougal2 :lol:
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dougal2
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Re: Scene optimisation tips

Post by dougal2 » Wed Mar 24, 2010 7:07 am

CTZn wrote:
I'd rather not mention the how publicly because we do not want users to spread biased renders by lack of control (it's a very advanced parameter). Actually I must refer to my superiors regarding public policy on those items, please hold on dcm !
Scratch this, good job dougal2 :lol:
Well, I'm not exactly saying that it is a good idea :wink:

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dcm
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Re: Scene optimisation tips

Post by dcm » Wed Mar 24, 2010 8:08 pm

CTZn :

for example, i want to make "supermancy white" interiors as on
http://www.archdaily.com/4806/dolomites ... chitecture
With vray, its pretty easy, but any tips, how to achieve this in Indigo ? (i know , its possible, but rendertimes... ). As Zom-b said, is bad to use super white as diffuse for walls and 205RGB is kinda grey. Playing with reinhard doesnt help. There is no choice...wanna white?Okay, wait 2 days. :idea: Probably, this could be achieved by placing huge emitters to windows...but again, more layers, bigger rendertimes.

Im asking cuz i need to make superwhite interiors for my next customer and im not sure if indigo is good choice for this kind of job :(

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Re: Scene optimisation tips

Post by OnoSendai » Wed Mar 24, 2010 9:34 pm

Interesting problem dcm; when you need white walls, then you really do need to make them white :)
As for rendering modes, I would recommend bidir with QMC (e.g bidir with MLT off). Should be fastest for white interiors.
I have some ideas for faster rendering of such scenes, but they will have to wait for a while.

nik

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Re: Scene optimisation tips

Post by Godzilla » Wed Mar 24, 2010 10:32 pm

For what reason do RGB 205+ colors take longer to render?
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Re: Scene optimisation tips

Post by Zom-B » Wed Mar 24, 2010 11:21 pm

Because a pure white wall reflects light just like a mirror :)

These two links may help ya understand:
http://www.indigorenderer.com/forum/vie ... 251#p85251
http://www.indigorenderer.com/forum/vie ... 307#p47307

If you want some pure white walls etc. just get it by tonemapping! if your other materials aren't 205+ too it should be a very easy task :)
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dcm
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Re: Scene optimisation tips

Post by dcm » Thu Mar 25, 2010 1:29 am

OnoSendai wrote:Interesting problem dcm; when you need white walls, then you really do need to make them white :)
As for rendering modes, I would recommend bidir with QMC (e.g bidir with MLT off). Should be fastest for white interiors.
I have some ideas for faster rendering of such scenes, but they will have to wait for a while.

nik

Bidir with mlt off? Its mean PT bidir or ? in max exporter is possible to choose mlt, tp or both with bidir.

@Zomb - what about mini tutorial you could write ;)

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Re: Scene optimisation tips

Post by suvakas » Thu Mar 25, 2010 3:26 am

Yes, PT = MLT off in Max.

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