Scene almost unworkable despite decent PC

vincentblackwood

Hi, I think I have a pretty good PC and it generally handles almost anything I throw at it in Daz perfectly fine - Ryzen 9 7900X, 32 GB RAM, and RTX 3060 (I know that's not a top of the line GPU, but it has handled complex scenes well).

For the first time, what I thought should be a quite simple scene seems to just completely choke up my entire PC when I switch to Iray (literally even the mouse cursor lags heavily). If I try to render directly, it took 30 minutes for like 11 iterations or so in 1080p, which is absolutely abnormal as well.

It's this environment which is gorgeous: https://www.daz3d.com/grassy-grove and I can feel it's quite heavy by itself when in Iray but still manageable - but when I added a dressed G8F character and a cat ( https://www.daz3d.com/daz-house-cat-with-dforce-hair :3 ) that I used in past scenes without problems, I get the above result. I've done far more complex scenes without big issues, but this is just impossible to work with.

Any idea what could be causing this and if there might be some kind of bottleneck I can get around? Here are my hardware render settings. Thanks in advance for any help.

barbult

Save your scene. Close Daz Studio. Wait a minute or so for it to close in the background. Restart Daz Studio. Load your scene and render. Does that work better? Closing and restarting Daz Studio will force Iray to release any memory it is holding on to, like for trying to do an Iray Preview or rendering previously.

Check your G8F and make sure the SubD is not set too high (in Parameters pane). Render SubD of 3 should be enough for a close up. If you have the whole G8F visible, you can probably get by with 1 or even 0. The higher you have SubD set, the more memory it uses. Each increment of 1 uses 4 times as much memory. 

Do you have Instancing Optimization set to Speed in the Render Settings pane? That would be bad for this scene. The scene uses instances heavily. Set Instancing Optimization to Auto or Memory. 

Do you have the Post Denoiser Available set to On in the Render Settings pane? Turning that Off can save some VRAM, but it may also require more iterations to get a clean (not noisy) render.

What version of Daz Studio are you using? Which of the products render settings are you using? Does your RTX 3060 have 8 or 12 BG or VRAM? It is recommended to have 2 to 3 times as much system RAM as GPU VRAM, so your 32 GB is probably adequate, but not super.

In the Render Settings pane, you can set CPU Affinity and reduce the CPU Load Limit to use fewer of your CPU cores, to help keep your mouse usable.

Install GPU-Z (free) to monitor your graphics card VRAM usage and other parameters. You can see how much VRAM your render is using and whether the GPU is being used or whether it has fallen back to CPU (SLOW).

When rendering, don't have other applications open.Even Internet browsers, which can be memory hogs.

I have an RTX 3080, which has 10 GB of VRAM. I have 32 GB of system RAM in my computer. My CPU is much older and slower than yours. I rendered Grassy Grove with Render Settings HFGG Forest Morning Haze and Camera 1. In about 8 minutes, it rendered 1000 iterations and used only 4 GB of VRAM. I Can navigate around in the Grassy Grove environment in Iray Preview. It is somewhat slow and jerky, but it is usable. I don't have a G8F or house cat with fur in my image.

Try the suggestions above and see if any of that helps.

Lorraine

Pretty sure it's the Grassy Grove causing the problem. It is gorgeous but it is also VERY heavy, having a thousands of instances which slows the view point way down. Perhaps turn off the instances when you are posing and turn them back on to render.

Padone

A typical trick for large scenes is to render the environment first, then use it as a background plate to composite with the figures. This also has the advantage that you can render your ackgrounds once and use them for other scenes. However, this can't always be done depending on the composition you need.

Another trick which usually works is to render in the viewport, that is, use the viewport in iray preview mode. For some reason this takes much less resources than rendering, but has the disadvantage that your render is limited to the viewport size.

Also of course you can use the scene optimizer or polygon reduction but this may affect the render quality again depending on your needs.

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

https://www.daz3d.com/decimator-for-daz-studio

kpr

"If I try to render directly, it took 30 minutes for like 11 iterations or so in 1080p"

It's flooding your VRAM and using CPU. (mouse use in viewport will be instances, @lorraine has tip for that)

• Scene Optimiser, if you have it, might help with the clothes, character and cat (also, if the character is clothed, hide all body-parts you can't see).
  • It won't help much with a heavily-instanced environment
• OR use @barbult suggestion and render background as separate image.

Trick is to find those few MB of textures/maps that are pushing the scene above your VRAM-amount <-- Scene Optimiser will help you do that (order by texture size, slash those not close to camera ... 1/2 usually okay)

Right now, said genius-plugin is on 50-60% sale (more if you're member and play the sales-boosters): https://www.daz3d.com/scene-optimizer

You might also use @lorraine suggestion to find the actual tree/foilage models, and - if you can given the view you want - hide them (not delete, cos of the instances).

vincentblackwood

Thanks a lot for all the replies! But specifically, this did it: 

barbult said:

Do you have Instancing Optimization set to Speed in the Render Settings pane? That would be bad for this scene. The scene uses instances heavily. Set Instancing Optimization to Auto or Memory. 

For some reason, it was set to Speed in this scene (never set it like that myself and seems it's normally Auto but not here), after switching to Memory it now actually works properly in Iray - it definitely feels "heavy" but doesn't completely choke my PC and can be worked with. (Also lowered SubD, that is also good to know.)

Overall a lot of useful knowledge here so thanks again everyone :)

barbult

Congrats on fixing the problem!  Thanks for letting us know what worked for you. That might help someone else searching the forum for the same problem.

alan bard newcomer

Padone said:

A typical trick for large scenes is to render the environment first, then use it as a background plate to composite with the figures. This also has the advantage that you can render your ackgrounds once and use them for other scenes. However, this can't always be done depending on the composition you need.

Another trick which usually works is to render in the viewport, that is, use the viewport in iray preview mode. For some reason this takes much less resources than rendering, but has the disadvantage that your render is limited to the viewport size.

 

still using a 1080ti and a titanX
scene below base render at 3000x3500 took 20 minutes 
the airpboat, the front boat, and the other three groups of characters were done two an a time average render time for each on about 3 minutes 
then stacked in PS
---
I can also switch and us this for human character instead of the Cats.  
Or switch and put the cats on the background with the ktds in it. 
The lion and tiger with dforce hair are always a separate render .. ususaly fast but the mats over load the card if done with a scene in also.