Incredibly slow render times for an optimized model
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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.
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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?
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@cuttingedge said:
(specially refraction)
There doesn't seem to be refraction in his glass material.
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@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.
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@martynaaas said:
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.
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.
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@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.
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Can you share the model so that we can test? Extensions> V-Ray> Pack Scene.
Also, have you purged out layers and components? Purge components then purge materials, otherwise you dont get rid of everything extra.
Finally, V-Ray BRDF Layers using Refractive materials will render faster than just adding a reflection layer on top of a transparent diffuse layer, but you have to have 3 dimensional geometry (thickened glass) for it to work properly.
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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?
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@martynaaas said:
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?
Use something like dropbox, or an equivalent, and share a download link. That's typically how I tell people to share models.
As far as the size is concerned, that's about right. V-Ray references a lot more information (textures, proxies, lights etc..) and those begin to add up when packing the scene because it collects everything on your drive and places it into a zip folder, the zip file will show the actual size of the model verses the Sketchup size (hence the 35mb to 129mb bloat after you packed the scene) This is normal and to be expected, but we may be able to further optimize the scene from there.
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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%...
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Your problem isn't your settings its your glass material. Light is calculated more slowly for transparency vs refraction. You'll see better results if you go through and replace all your glass materials with refractive glass (see attached).
To use refractive glass, you'll also need to make sure you thicken your glass planes (which it looks like you've already done). A one sided transparent plane causes problems because it takes more time to calculate the light through it.
I've also updated your scene settings and will pack your scene back up I post it here with a time stamped render once it completes. Its turning into a very nice render!
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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.
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Glad to hear it worked! Ill upload the file as soon as I have a chance. What kind of hardware are you working on at the moment? It was slow for me as-well (running a core i7 3770 32gb ram), but I cranked up the settings too.
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Using i7-4785t 32GB of RAM. It's ok until you start rendering something like this.
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