@valerostudio said:

You cant depend on solely exterior light to render an interior. You need to add lights, the same way you would need to light a space in real life. Sometimes I add a couple of planes just inside the windows to fake in some more light, but you definitely need more lights in your scene or you are going to get splotchy renders.

I have to disagree with you here. I use HDRI + VraySky most of the time which gives me more than enough lighting for any interior scene (considering that an interior has a right amount of openings). I guess your statement is more valid when doing night/evening renders.

@valerostudio said:

I stopped using light portals. The render times were isane and I did not find that added to the quality of the image, just use regular rectangular lights if you must.

It did increase render time indeed, although I was able to produce those sharp shadows on the ground. I guess it really depends on the quality of renders you're looking for. For this project, we are working on a high-end interior so producing qualitative renders is a must.

Going back to topic, I was able to reduce noise levels dramatically by checking Sub-pixel mapping option under Colour mapping menu. It's still a little bit noisy but not as much. Changing subdiv count under Vray Rectangle light options did not do too much (went from 8 to 64 and could barely notice a difference in noise levels but shadows got a little bit smoother).

I'm trying to render an interior scene and testing a few settings with Vray rectangle light set as light portal. I got those nice shadows where objects meet ground, however it got way too noisy now. Does this noise come from low subdivs of rectangle light? Or any other settings?

Using i7-4785t 32GB of RAM. It's ok until you start rendering something like this.

Thanks! I never actually studied BRDF materials so it's a new area for me. I've checked your material and it seems to be doing a little bit better, however not by much. I'm now thinking it might have to do with hardware that I use (pc is getting old).

On the other hand, I was able to produce some renders (took about 10hours on very low settings). Not sure if anyone cares but I'm attaching one of them (I might have photoshoped it a bit too much as I always do...).

Also, looking forward to see your updated scene settings.

Link to a file via Filedropper

I did some more research on it and found out that Vray takes longer to render with very high as well as very low render settings. I'm now thinking it might be the latter. Everything is optimized to a bare minimum, it has to be something with render settings.

P.S. Tried to render the scene on a monster computer which usually renders 5x faster than mine. In 3 hours was able to render 15%...

For some reason when I pack it, it gets to 129MB. I'm not sure I can attach such huge model onto this forum. Can I upload it elsewhere and post a link?

@cuttingedge said:

35 MB should be easy to handle. It must be some problem on the file. Try inserting it onto a new file.

What I also do is purge materials in vray. For downloaded blocks (not my own), I remove materials using material tools and reapply materials.

That's exatcly what I did. I do not have any unused materials. Every material was checked and reduced in quality/size just in order for this to render. I'm now thinking that it's because of light. I have a lot of it and it reflects everywhere. I'll try to reduce the number of Vray planes.

@cuttingedge said:

Yes glass it is. And i bet if its shopping mall, you'll have lots of glass everywhere. All materials with reflection and refraction (specially refraction) will definitely slow it down.

Other times, there could be one model or texture that could be the culprit. Keep all textures less than 1mb if possible. I suggest you insert everything to a new file and see.

How big is the file?

A file was 35MB only. I do not have any refractions nor displacements in my model. I do have however some reflections on floor material, and do have a lot of glass. On the other hand, as I have mentioned previously, I worked on much heavier models in the past with materials having all kinds of settings and did not have too many issues with it.

I also have some glossiness maps on textures that are important - floor materials, metal, and I believe marble. That's it. The rest of materials have only diffuse or simple fresnel reflection.

So I'm working on a shopping centre model which I'm trying to render in Vray. Now, due to a lot of geometry, many texture files and vast amount of lighting I quickly faced long render times.

Last night, I started optimizing model and brought it down to about 160k polygons (from over 2m), 35 textures (from 155, not looking for too much detail atm), put everything what's possible into components, brought render settings to the bare minimum, and still it takes half a day to render 1000px image.

I've checked all materials, reduced reflection subdivs, got I believe only 1 bump map for floor texture, the rest of materials only have diffuse and reflections (where needed).

I've worked with much heavier models, having over 2m polygons and rendering fine at 8000px resolution in like 10hours. Have no idea what could be happening right now. Any suggestions?

P.S. A render seems to stop dramatically when rendering glass. I'm guessing it's because of many reflections it has to calculate but I'm not sure. Attaching all my settings.