We use 6GB 980ti’s with redshift for exterior rendering, it seems that VRay uses a lot more Vram. We wanted to know what GPU would be good for large exteriors, mainly grasses,trees, bushes. We were looking at 2080ti’s with 12GB but we are worried that will not be enough. Wondering if we need to get RTX Titans instead. Like to hear from others experience with large exteriors.
I’m not too experienced with gpu in general, but why not stay with redshift? I think redshift is a bit more biased and optimized then vray in that regard, I could be wrong though and would also like to hear what others have to say?
Vray is better right now for Archviz, also Vray has Distancemap which I use constantly.
You might do 2080 Ti’s with NVLink. You would get more bang for your buck than the Titan. I literally just ran out of VRam a few minutes ago on a 2080 Ti on a fairly simple exterior. 3D Displacement will do you in. I have an NVLink on the way but may end up converting this scene to Corona. If you’re going to be investing in new hardware anyway you might consider going the Corona\Threadripper route.
There is a good discuss in another thread on this forum, here is an article from corona that was referenced there:
Thanks guys the problems I’m finding is that corona renders much more realistic than Vray and actually cleans up faster especially in dark areas, but it takes forever to clean up say a lot of grass so it doesn’t flicker in animation. Vray CPU seems that it can render a large field of grass for animation much faster without even using Vray GPU. This will primarily be for animations. What do you guys think?
For stills I would use Corona all day long.
The realism aspect does not depend on the renderer. Vray or Corona can both produce identical results. GPU and cpu would be two different areas of rendering all together I would not compare them.
I don’t know I’ve done some comparisons with Vray vs Corona and for realism Vray just couldn’t match Corona.
2080 tis with the option for nvlink is probably the best option
Can you show me? I’m curious to see why people are left with that impression.
In terms of GPUs, the 2080 Ti is a good choice; you can fit quite a lot of geometry in it and we have on-demand texture loading for the bitmaps. Also, we will be adding RTX support soon and it has its own ways to compress the geometry on the GPU.
Best regards,
Vlado
Yeah I’d be interested in seeing this as well. The definition of realism is a broad one, I’ve seen photo realistic renders from vray for years, ones you could not distinguish from reality, same from arnold and corona. If you strip off the textures, and just render on grey, you surely would get very similar results.
Hi Vlado - I’m not the OP but just jumping in to say I emailed you some comparison images with notes. I think I remembered your email right, if you don’t receive it please let me know.
Thanks!
Daniel
I’ll post some comparisons in a while, stuck busy at work right now.
Bertrand benoit just posted a pretty large exterior that fits in around 7 gigs of gpu, might be worth buying and picking apart - The Spring
On the vray vs corona thing I betcha it’s just default tonemapping 
- Vlado the scene converter can swap pretty easily between the two renderers now can’t it? As in we could run the exact same materials and lights in both renderers and look at where the results differ?
When using only Diffuse color you can see the difference in shading between the two renderers. You can see here how Corona has more depth to it especially in the Trunk and Branches. This is something that I see Corona adding to every object it renders, and because so it gives everything more depth and detail. I can always spot a Vray render cause it lacks this and lacks the depth and extra edge of realism that Corona gives.
Another thing is shaders, I find Corona to give much better results with it’s shader especially for things like Translucency of say leaves or vegetation (I’ll try to make a comparison of that also). Also minor things like how it deals with bluring textures way to much and you have to go around to every texture and lower the blur for it to look right, like in the example below where Corona just renders the texture correctly.
Interesting comparison. You can see in the shadows though that some different contrast is applied. At least the huge Shadow in the back on the ground has to much so that we can really compare. I wonder if it would look similar if three tonemapping and contrast would match. Hard to tell…
It’s a fair point on the texture blurring and might be good to swap some defaults - we normally drop to 0.5 blur on all of ours. I’m not sure what the standard corona render settings are but it definitely looks like it’s adding in a bit of a contrast curve - if you have something like nuke you could put the two images above through it’s colormatch tool and it’ll generate the difference between the two as a colour lut - you can load this in the vray buffer. Personally I’m in vfx and every camera has a slightly different curve to it so we always take the curve off the image to make it flat / linear, render our vfx to this and then reapply the camera curve to both afterwards. A big part of photorealism (aka making something look like a still off an slr / movie camera) is that one of those camera’s job isn’t to record colour and brightness accurately, it’s to make a pretty picture. To do that they take the image data and accentuate certain parts of the result to make it more pleasant - if you take the same picture on a nikon, canon and sony you’ll get three different images as all three manufacturers are going to choose different parts to feature. Vray doesn’t do any of this so it can tend to look a bit flatter than some other renderers which add a little bit of a default look, some artists might really like that as they want to get a finished image right from the frame buffer, some others might want to have the purest data they can get as they’ll be doing a lot with it after!
Yeah the blur sucks especially when you have loads of textures to correct. Sorry I do not have nuke nor use nuke. The curve or whatever you want to call it does add a lot more detail and depth to the render, I found this in many test renders I did. Corona and Fstorm both have a great curve for realism. I’m surprised that a curve can pull so much highlight into the trunk of the tree and the branches, if that’s whats doing it. I would love to see a curve matched to coronas in Vray, so far I cannot reproduce.
Is the blur really greater in VRay than Corona by default? CoronaBitmap and also max bitmap always defaults to 1.0. Regardless of render engine I often drop that to .5 or .2 (or .01 for opacity maps.) Is there something else forcing greater levels of blur in VRay by default?
No both Corona and Vray blur is set at 1.0, but Vray for some reason blurs the texture a lot, especially at angles.