Why is this scene grainy?

crosswind

I have developer account and I've read it before ~
But I said NVlink is gone on Ada L., did I mean this sort of technology is dead / discontinued or sth.? !   The above thread is about Link and Switch between servers in data center, which have nothing to do with graphics cards in consumers' hands, is there any relevance to my point ?

Back to his 'big scene', if he does nothing with optimization,  no render will go for GPU.  If he uses Scene Optimizer to properly downsize the texture maps, he might have the chance.  Lots of my friends and students have adopted this simple method to resolve the rollback issue... Why not give it a try? 

PerttiA

If you do not see the relevance, there is no point in further bloating of this thread with unrelated things.

The fact is that the OP has only 8GB's of VRAM on their GPU's, which started to be limiting already some two years ago. Common knowledge on these forums is that 8GB's of VRAM is really not enough anymore if one is using somewhat recent DS, with the latest drivers and using somewhat recent assets in the scene and of course W10. The around 4GB's of VRAM that's available for Iray rendering (on a 8GB card) is maybe enough for 3 G8/G8.1 characters with clothing and hair without environment/architechture, or 3 characters with environment architechture if one does know how to build the scene in a way it doesn't go over the available VRAM.

crosswind

Are we following the same thread?  The OP has got two RTX 2080 cards, total VRAM is 16GB ... but he only ticked one in devices list for rendering ...

Let's stop this conversation~ I don't see any point in arguing about these facts...

PS: Some basic calculation of VRAM consumption (appr.):
- One Daz instance: 450 - 500MB
- One bare G8 base fig: 800 - 900MB (Geo + Tex)
- iray Engine:  2.2 - 2.4GB
- 100K polygons: 10-15MB; x4 per Render SubD Level +1
- Tex maps (single map before compression): 1K - 4MB, 2K - 16MB, 4K - 64MB, 8K - 256MB....

PerttiA

Also it is well known fact, that when rendering Iray in DS, the amount of VRAM available for Iray rendering is the amount that is installed on the GPU with the most VRAM minus the amount of baseload (around 3.5-4GB's on W10), it doesn't matter what is written elsewhere - There is proof enough within these forums that 2x8GB's does not 16GB's make.

crosswind

I said total VRAM man ! not the available VRAM for rendering while making calculation... Let's stop it okay, stop it ~~.  My English is poor enough... but as a loyal user I've been with Daz for nearly 7 years, now it sounds like I'm a noob ~

One better have real hands-on experience with multi-cards + enough meaningful tests before giving any relevant guideline...

chris-2599934

pectabyte said:

So what do you recomend I do? Talk to me like im 12 years old. :D

Ok, sonny...

The stuff in that picture is more than your GPU(s) can cope with, so it's being dropped to the CPU instead. This will still generate an imageof the same quality, but takes MUCH longer. Your settings (the default ones) tell it to stop after two hours, so that's what it does - grainy or not. Here are three possible things you can do...

1. Increase the Max Time (secs) parameter to as high as it will go: 259200 (3 days!) That should be long enough for anything, though it won't actually take that long. Set your scene rendering, then go to bed or go to work school (sorry, forgot you were 12) or do some other thing while it's brewing. Note that you might find after several hours that it's still saying it's only 80% complete, but looks perfectly fine to the human eyeball. In which case you can stop the render at that point - what else were you planning to look at it with?
2. Decrease the amount of stuff in the scene until it's something youe GPU can cope with. You can do that by removing stuff altogether, by decreasing the resolution of map images, by removing images in surfaces and replacing them with solid colours. MattyManx's Resource Saver Shaders (and its successors) are great for this.
3. Shoot your scene in separate parts, then composite them togther. You have seven people in your scene, suppose you determing that your GPU can only cope with four at once. You shoot one render with the leftmost four people in it, and one with the rightmost four (the guy in the middle is in both renders). Then you go to photoshop (or equivalent), layer one render over the other, and delete the empty bits from the top one so the characters show through from the bottom one.

If this is a one-off image, and most of your renders aren't going to be this complicated, I'd just go with option 1. If you'll be doing a lot of them, then explore 2 and 3.

PS. I'd avoid using the denoiser on any image involving people. It does an ok job on plain surfaces, but human skin just looks horrible.

kirbawirba

PerttiA said:

Ok, the card has just 8GB's of VRAM and you are running W10, that means you have around 4GB's of VRAM available for Iray rendering.

Wait... Does this mean that using W10 limits you to half the memory of your card while rendering?? 

 

Edit: sorry, clicked the wrong button and created a new response below... disregard this one...

kirbawirba

PerttiA said:

Also it is well known fact, that when rendering Iray in DS, the amount of VRAM available for Iray rendering is the amount that is installed on the GPU with the most VRAM minus the amount of baseload (around 3.5-4GB's on W10), it doesn't matter what is written elsewhere - There is proof enough within these forums that 2x8GB's does not 16GB's make.

I had no idea this was a thing... How do we improve that? Will upgrading to 11 help? 

pectabyte

Here is a 4k render. Its a little clearer but is still very grainy. I'm not sure what to do.

https://www.dropbox.com/s/e0xk7j2qd0u24z2/4KTest.png?dl=0

 

chris-2599934

Have you tried the things I suggested?

PerttiA

kirbawirba said:

PerttiA said:

Also it is well known fact, that when rendering Iray in DS, the amount of VRAM available for Iray rendering is the amount that is installed on the GPU with the most VRAM minus the amount of baseload (around 3.5-4GB's on W10), it doesn't matter what is written elsewhere - There is proof enough within these forums that 2x8GB's does not 16GB's make.

I had no idea this was a thing... How do we improve that? Will upgrading to 11 help? 

Downgrading to W7 pro or ultimate would give you about a 800MB's more VRAM for Iray rendering, there hasn't been enough relevant information (with proof) on how it is with W11 yet.

W10 is not taking all that VRAM, W10 takes about 1GB, but then DS needs some, the scene requires some (even before hitting render) and when rendering, the process needs "Working space" in VRAM, which is by default 1.9GB's in current versions of DS (1.7GB's in DS4.15) - What's left, is available for textures and geometry (around 4GB's on 8GB GPU), textures usually taking 10+ times more VRAM than geometry, unless one is using high SubD's.

When the size of the scene is near filling the available VRAM, DS can lower the amount of reserved "Working space", but if there's less than 1GB left for it, one starts noticing the rendering slowing down.

PerttiA

pectabyte said:

Here is a 4k render. Its a little clearer but is still very grainy. I'm not sure what to do.

https://www.dropbox.com/s/e0xk7j2qd0u24z2/4KTest.png?dl=0

Rendering at 4K is not helping 

Matt_Brown

Back to the original problem...

You either need to invest in expensive video cards with more VRAM, have less characters in your scenes, or to use a product like scene-optimizer to save rescouces and get it all to fit on your existing card setup.

https://www.daz3d.com/scene-optimizer

I used Scene-optimizer to fit all these characters onto one 3060 card: https://www.daz3d.com/gallery/user/6666647997775872#gallery=album8881820&page=1&image=1203924

crosswind

pectabyte said:

Here is a 4k render. Its a little clearer but is still very grainy. I'm not sure what to do.

https://www.dropbox.com/s/e0xk7j2qd0u24z2/4KTest.png?dl=0

 

Seems no big change ~ so what have you done since we suggested a lot~  Tried Scene Optimizer ? Rendered with you GPUs or still CPU? ...