Differentiate sampling/quality of objects in rendering

[Jon Berntsen]

Hey!

 

I have been spending some time thinking about how I can speed up my renders. My conditions are as follows:

- Need of high GI and good sampling for clear and crisp details on wooden buildings, including sidings in the darker parts of the god damn universe (or as it sometimes seems).

- I can get away with less quality on sampling and GI for the vegetation.

 

Now, using the same settings on my vegetation as on the building, especially the stuff in front, makes it render unnecessarily slow. I can use region rendering for stills, but it's not optimal. I can in fact also render the entire image with the "building quality" if I have time overnight. I am often working with stills at 6000px width or more, so reducing the quality on vegetation will make a significant difference for me.

 

Not to talk about animations in HD or 4k in the future.

 

So I am wondering if there are any possibly ways to separate the quality somehow in one single frame without re-rendering with less quality in the gi or sampler.

I know that adaptiveness in the irradiance and aa sampler is there (and I use it), but I can't see how I could solve it with that.

 

Have anybody thought about this issue before? I am aware of that I can reduce the gi interaction on object level as well, but I need the right amount of GI. So that would rule out that as an option too. I could definitely change the max subdivs in the sampler, but then I would need to rerender or do a region as mentioned, which is not a solution for animations.

 

Any ideas?

[RyderSK]

If you're fine with noise in vegetation, that you can tweak your samples ratios in scene to reflect that.

 

Go Grant/Akin's optimization method, where you keep high-enough AA clr threshold= 0.015 (with for example 1/15 Min/Max AA, it's fine if you don't have motion blur/DOF) and manually set your secondary subdivs on materials based on priority (instead of default 8).

 

But to be honest, if you have your vegetation setup correctly (filtering off on alpha maps,etc.) and choose reasonable AA clr threshold Universal solution scales pretty good across resolutions and great quality/time.

With Vray3, there is almost like zero need to do anything outside of proper Universal solution/Min. shading rate.

 

No amount of optimization in world will save you "lot" of time in Vray with all the counter-balancing going on (to avoid users f****** stuff up too much). And nothing will let you render 4K animations at home :- ).

Best speedup is to buy more computers.

[Jon Berntsen]

Thanks for your response, Juraj.

Secondary subdivs on materials, is that something that came with vray3?

Sounds like we should buy vray3 as soon as possible.

 

We have some render nodes setup with backburner manager/dr in a render farm, but i would still like the vegetation to render a little faster with still having the qualit on the buildings themselves to be top notch.

 

Is the Grant/Akin setting based on dmc sampler or adaptive subdiv?

[RyderSK]

I am sorry, I missworded it incorrectly/confusingly, I meant secondary rays, but that can be equaled to subdivs, as light/materials/dof/etc.. are all computed after primary rays by AA sampler. And what you would in such case want, is less primary rays traced (subdivs computed) from AA overall, and more done by secondary rays from the above mentioned effects. And you can set those individually (set higher glossy subdivs for your architecture, but keep it low for vegetation).

 

But with Vray3 onward, even this is complete waste of time. The universal approach works so dramatically well in combination with Min.Shading Rate (the only addition in Vray3), there is no need to optimize anything. I don't optimize anything, ever, from giant exteriors to highly glossy interiors. No tweaking of anything, all default.

 

DMC Sampler is largely untouched in all situations, just keep some default adaptivity (0.85 for example) and that's it, there is nothing else to touch. Everything is governed within AA (adaptive subdiv) sampler.

[Zdravko Barisic]

For the first step, turn OFF fitlering maps in main tab of VR.

 

http://help.chaosgroup.com/vray/help/150SP1/images/controls/options.png

[Scott Schroeder]

I am sorry, I missworded it incorrectly/confusingly, I meant secondary rays, but that can be equaled to subdivs, as light/materials/dof/etc.. are all computed after primary rays by AA sampler. And what you would in such case want, is less primary rays traced (subdivs computed) from AA overall, and more done by secondary rays from the above mentioned effects. And you can set those individually (set higher glossy subdivs for your architecture, but keep it low for vegetation).

 

But with Vray3 onward, even this is complete waste of time. The universal approach works so dramatically well in combination with Min.Shading Rate (the only addition in Vray3), there is no need to optimize anything. I don't optimize anything, ever, from giant exteriors to highly glossy interiors. No tweaking of anything, all default.

 

DMC Sampler is largely untouched in all situations, just keep some default adaptivity (0.85 for example) and that's it, there is nothing else to touch. Everything is governed within AA (adaptive subdiv) sampler.

 

In Grant's video about Vray 3, he still tweaks his subdivs in materials/lights/GI but no where near as high as what you would do with older versions of Vray. For example, his brute force before was around 128 but now he's at around 24-32. However, he keeps the min shading down to around 2 with AA around 1/8. Are you saying you can keep everything at 8 (mats/lights/GI) and just rock a high AA say 1/16 and a higher min shading rate say 4-6ish and still get noise free or minimal noise renders in a reasonable render time?

 

I've got to admit, while I understand what min shading rate does, my brain also melts when I really try to wrap my head around it. Me thinks part of it is the part of my brain that wants to do the old ass Vray way of high individual subdivs.

[RyderSK]

Hi Scott,

 

yes exactly like that, I have found the sweet spot to be around 8-12, but this is largely for interior, and can do away with less for product studio or exteriors. I largely also use Progressive Image sampler set to 0.00 clr threshold and just watch until it looks really good :- )

I use 1/100 though, in both Adaptive Subdiv and Progressive Sampler scenario.

 

I think min. shading rate is much more logical than former global subdiv multi, as it doesn't get divided by Max AA sampler, but instead work as direct ratio between primary AA ray and Secondary (Min.Shading rate set to 8 will be therefore 1:8 AA/Rest).

 

I find the time to be very reasonable because the color threshold is so independent of resolution. If you tweak something manually, you always have to redo it once you decide to switch for much higher resolution otherwise you end up with extreme time. That's what I see often happens to people on Chaos forum when they tried to adopt this approach.

With universal I just go from fullHD to 4k with simple switch of resolution and nothing else to tweak. That's a lot of time and nerves saved.

I don't have much particular reason to bother optimizating only to get 30perc. speedup. If I need drastically faster time, for animation, I just switch to regular IM/LC workflow with 1/8 Min.Max but again use Min.Shading rate to force glossy subdivs instead of manually tweaking each subdivs individually.

 

I found Grant's approach to be quite valid in 2.4, even though still not very enjoyable, but with Vray3 being so much drastically better, I just see no reason to do so anymore. Universal works great.

[komyali]

 

No amount of optimization in world will save you "lot" of time in Vray with all the counter-balancing going on (to avoid users f****** stuff up too much). And nothing will let you render 4K animations at home :- ).

Best speedup is to buy more computers.

 

Yea and I thought it too till I found this...

I have i7 920 but its not overclocked and more ram than him, also I have i7 3930k but still I have problem rendering big scenes... his frame isnt best but it is very nice for 5 minutes rendering... I think profesionals are stingy on their know knowledge about vray so if you want to be professional you need to practice on your own and spill a lot of your own blood

[RyderSK]

If I was in my regular sarcastic mood I would just say: That was amazing !

 

But since I actually am, I will also leave it at that :- ).

[Nic H]

great video and a nice result

[Jon Berntsen]

Yea and I thought it too till I found this...

I have i7 920 but its not overclocked and more ram than him, also I have i7 3930k but still I have problem rendering big scenes... his frame isnt best but it is very nice for 5 minutes rendering... I think profesionals are stingy on their know knowledge about vray so if you want to be professional you need to practice on your own and spill a lot of your own blood

 

Rendering millons of polygons with scattered trees from distance in 1280x720 has not been a problem in ages. Try going on closeup vegetation in front of camera and still maintaining a superb quality on the aa and gi between intricate sidings and window details, in 6000x6000 or more, and you will understand why I initially was looking for a way to loosen up on the quality on the vegetation going further and more general than tweaking materials, and keeping it in one render.

 

Ryder, seems like you have a very deep understanding of how vray work, congratulations for that. there are a ton of different approaches, and you have to choose one for your regular workflow. The one you are describing about changing only the resolution is interesting. But if it is true that vray3 is so much better, I think I will put this topic on hold for my sake until I get vray3. Never heard about universal though, so seems like I have some reading to do on vray3

[komyali]

yep, I know, that is the reason I hate trees

[RyderSK]

Jon, Vray3 is indeed much better, and I am very slow, conservative adopter, much to popular belief of some of my friends :- ) I was very positively surprised in how much, and that is despite trying it on like 7 months later since Bertrand Benoit assured me it's quite excellent. It is.

 

{disclaimer: I do still think Corona has better core and better future ahead, so my work is still mainly..in that}