I just bought Evermotion 20 anniversary scene to test some things. And this is what I found:
In VRay, inicialization proces takes about 10 minutes, it was super slow. And whole scene takes over 200 GB of RAM. And when I stoped the render, change something and start render again max crash.
In Corona, inicialization process takes about 10 seconds, it was super super fast. And it takes around 80 GB of RAM.
You own both render engines for a years. Can you please do something about this in VRay finally? I really dont understand why Corona is so so fast in inicialization (Corona version 14) and takes so less RAM. Because final image is pretty much the same.
And second thing. There is displacement on all big trees in Corona.
VRay has no displacement on those trees and it is still so slow on inicialization and the amount of RAM VRay takes even without displacement is enormous. On other hand Corona takes so less RAM even with all those displacement in the scene.
Is the scene set up for V-Ray? If so, it sounds to me that there might be a lot of V-Ray-specific stuff (VRayDisplacementMod, etc.) that Corona probably ignores. It is not an adequate comparison if you simply switch the renderer.
It is two different scenes - VRay and Corona. And actually there is a lot more displacement in Corona then VRay. You can buy it on Evermotion (5 euros) and look at it please. Inicialization is super slow on VRay and takes much more RAM.
Evermotion were kind enough to provide me the scene. Which camera view were you testing with?
EDIT: I did some initial tests on the camera “exterior_front_002_43|0|145” and I’m getting similar results between V-Ray and Corona (around 2 min of prep time before rendering starts). V-Ray 7, Update 4 takes around 47GB RAM; Corona 15 - around 44GB.
Hmm, that is really weird. Do you use IPR or regular render?
I put scene on really fast M.2 disk and it is the same. For some reason I am waiting and RAM useg goes up to around 220 GB and then start to calculate Light Cache. I wait around 5 minutes. But I had corona definitelly faster then 2 minutes.
I think I dont have this problem somewhere else.
One thing, I am on Windows 10. I assume you are on Win 11. Could this be a problem?
Production rendering. Windows 11. Here’s a screenshot (the render is not yet completed). I just opened the scene and rendered; haven’t touched the settings. Using ForestPack 9.1.5. Based on what I see in the tree proxy’s material, there is both displacement and bump.
I looked at total RAM usage in Win. I will render again and see what VRay say. Btw there is a tool in VRay to see what takes more time, but I forget where it is and how its called.
Trees look the same as mine. There is displacement in material but not so much in render. I didnt look into it to see if some settings make any difference. But this is how close trees look in Corona. Displacement map is the same.
I click render and it waiting, nothing happen only RAM usage in Win go up to around 180GB in three minutes or so. But 3ds max and VRay doesnt do anything, just only RAM raise. And then VRay start initializing and computing LC and show first render. But RAM usage is already that high.
I managed to reproduce the high RAM by actually enabling the displacement of the trees, scattered with FP. Turns out scattering displaced objects with FP does not work out of the box; you need to enable the “Non-geometric object” option (FP > Geometry) for each object so that the generated displacement goes through. The problem is that by doing so, the scattered displaced objects seem to act as copies rather than instances (displacement is generated for each), which leads to a massive RAM spike.
Tested this on a simple scene and can confirm. As a reference, this does not happen with ChaosScatter.
As for why it works in Corona, I do not know yet. I’ll ask them. Corona displacement probably works differently.
EDIT: Corona guys told me they are using their own screen-space displacement.
EDIT: I’ve logged an issue for this (VMAX-15706) to report to iToo.
I dont have non-renderable objects selected in Forestpack. But even when I disable displacement in VRay settings, everything is the same. Compiling geometry takes ages, RAM in this stage goes higher and higher and then Embree again pretty slow and AFTER that already around 200GB in Win, then fast LC and render. And in render around 230GB.
And when I stop render, few seconds VRay unloading RAM but then it stops. Still 200 GB using and nothing happen and I have to kill max. Non of this happen in Corona.
I’ve no idea what could be causing it if you’ve disabled displacement (from the global switches, right?). You must have touched the settings of the original scene, since, as I’ve already posted my results above, it doesn’t happen when you just open and render.
Please, redownload the scene from Evermotion and see if it happens without touching anything.
