Long rendering times with walls and Iray?
daslicksta
Posts: 13
Hey everyone,
I'm just starting to get into rendering things in DAZ and have come across an issue I can't figure out. I set up my scene with lights and an einvorment that has props, a character, walls, floor, and ceiling. I tried rendering the scene the way I wanted but noticed a really long render time. I took away objects, one by one, and finally got it down to just the walls. My quesiton is how could the walls be slowing down my render so much?
Thank you for your time.
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
Any windows in those walls? Glass seems to slow down rendering, at least for me.
No, no windows. Just a plain wall (or so it seems).
Hey everyone,
I'm just starting to get into rendering things in DAZ and have come across an issue I can't figure out. I set up my scene with lights and an einvorment that has props, a character, walls, floor, and ceiling. I tried rendering the scene the way I wanted but noticed a really long render time. I took away objects, one by one, and finally got it down to just the walls. My quesiton is how could the walls be slowing down my render so much?
Thank you for your time.
threads merged, please do not start duplicate threads in different forums. It tends to end up with people giving the same information twice.
How are younlighting the scene? HDRIs and disant lights will be blocked by the walls.
The enviroment I'm using has a "render ready" setup that I just loaded and customized. I think the only light source in here is a sun dial in the middle of the room, on the floor. I just tried deleting the sun dial and putting other kinds of lights in there but still have the long render time.
The Sun comes from outside so, like HDRIs and Distant lights, it will be blocked by walls.
I understand that, but when I try replacing the sun dial with other lights, I get the same problem.
Are you using local lights - spots and points - placed inside the room? They may need to have fairly high luminosity to provide enough light - especially spots as they are still directional and so will be relying on indirect light for some walls.
I tried putting a good amount of lights in there, and increasing the spread and intensity. Nothing seems to be speeding up the render.
Sounds like you are CPU rendering. Anytime I do an indoor scene I can count on the render lasting almost the entire 3 days and sometimes 3 days that I allocate to the render. It usually takes almost 2000 writes by the render process to the image (1960+ writes).
I have gpu check marked, and optix accel. The only thing I can think of is there's some setting under the enviorments tab under rendering that shouldn't be on/off. I'm still new to this so I wouldn't know what to look for. Maybe the textures on the wall are weird? Again, I don't know what to look for.
Render settings set to scene only?
Yea, tried setting it to that but didn't seem to matter :/
What ready-made enviroment package do you use for this scene?
it's the i13 doctors office
https://www.daz3d.com/i13-doctor-s-office-environment-with-poses
Well I think optix accel only makes sense if you are using optix dynamic cloth which hardly anyone does so that would be the 1st thing to uncheck.
Next thing is make sure render quality in the render settings is only 1.0.
Turn on Architectural Sampler (only for scene with building & room & such I believe is it's only usefulness)
Turn off Caustics Sampler (is good for water, liquids, and materials that use caustics - very common to use caustics in water used in swimming pool renders and such things).
I think that covers the most common slow-downs.
Of course converging at 99.5% compared to 95% takes more time. Rendering a 4K image takes longer than a VGA image. And so on.
The one thing you may of not considered is the scene you are rendering is too large for your video card memory and so is being CPU rendered and giving you render times like I am used too instead of what you are used too.
Optix Acceleration and Optitex Dynamic Clothing are completely unrelated.
A lot of the settings are default. I looked over the ones you listed and they seem to be set to what you've specified.
I'm trying to render one image at 1080 resolution. I didn't think it'd take around 2 hours to render one image, seems like it should go faster.
My specs:
Windows 7 Ultimate 64bit
Intel i7 860 2.8ghz
14 gig RAM
gtx 1060 6gig
My computer isn't that terrible, is it?
Your computer isn't terrible, no. It should do OK with rendering.
However, as people have said above, lots of things in a scene can kill the render time. I have found that indoor scenes are way longer to render than outdoor onees, because object-based lighting is needed rather than HDRI lighting, and object-based lighting (with emitters, etc.) takes much, much longer to render than an equivalent scene in HDRI, almost no matter what else you do (even if there is nothing else in the scene but a single character, no walls, but you light with object lights rather tha HDRI, the object lights usually take significantly longer). I'm not sure exactly why this is, but I always want to kick myself when I write indoor scenes because I know the render times take longer.
Anything with reflective of transmissive surfaces (metals, glass, mirrors) will raise render times as well.
Sounds like you may be dealing with a similiar problem to one i had recently....
https://direct.daz3d.com/forums/discussion/174756/weird-grain-pixels-on-interior-wall
TLDR: The walls or floor may have a material / texture on them that is much more complicated to render.
What does Optix do? I mean besides acceleration for some people? A search shows some people guessing what it does. Is it some sort of AMD special instruction set?
It accelerates ray sampling by performing some tracing algorithms for a particular kind of mesh geometry that most Daz products don't use. So IOW, it often has little or no benefit. Some people have posted remarkable benchmarks with it on or off, but those are often suspect if they started timing when they hit the Render button, rather than when the first iteration came through. Any benefit also depends on what's in the scene.
For the OP, the doctor's office appears to be a closed set, so sunlight/environment dome settings will have little or no effect. Any light coming through the windows will be indirect, and may require very lengthy render times.
The overhead fluorescent lights may or may not be efficient. It depends on how many divisions the geometry has, and if it's accidentally double-sided.
You can test what might be causing the slowups by first hiding the walls and ceilings, leaving the props and characters. Allow the default environment dome to help light the scene. If the ceiling is a separate object, try adding the walls back in, and render without the ceiling, again letting the environment dome provide light.
Thanks guys, I'll give some of these a test.
Honestly, so much of this has to do with lighting, in my experience. Try some ghost lights or some other light systems to see what happens. I think Richard was on the right track.