Heavy Scenes Renderstart-Times extreme slow

[PdZ]

Dear Chaosgroup,

A lot of things are absolutely amazing in V5 but the essentials are those who causes xtreme headaches to me.

1. Rendertimes in General 2. Renderstart-Times.

2. I dont know what or why this happens but on my current scene when I hit the renderbutton (production render in VFB) than watching my taskmanager: It uses about 5% CPU and like 2-3 MB/s Networktraffic and i can wait (for real) about 10-20 minutes before Vray even start the rendering. I mean: Once this ridiculous time has passed it begins to "Prepare" Scene for frame and compiling geometry.

Iam really exhausted to nerd crack through those conditions.

Also rendering times are not even close to 3.7.

Iam really exhausted.

[PdZ]

I will increase the verboselevel in settings and post the console-output later. The scene is absolutely to big to share or send.

[sirio76]

Can we see a screenshot of the scene?

[PdZ]

Iam unfortunately limited to show anything because of NDA to my clients. But I can explain the scene:

Its an Office from outside. Ramusage 60GB.
CPUs: Threadrippers 32 Cores 2x and 1x Ryzen 9, 12 Cores. So in sum: 64 + 64 + 24 = 152 Threads.

AA 1:24
LC 3000
Rez: 5000*2800 pixel
Renderingtime was 10hrs.
Theres one change which could have impacted this rendertime a lot and it could be my fault. I changed max transparency depth to 200.

But thats not the topic. I send a video (which I will speed up) and the Vray Log in about the next hour.

About Materials: Nothing Special here. I used two HDRIs because of that amazing new feature to render once and via Light Mix disabling/enabling the HDRIs.

Materials are PBR and 1000px. I have also a lot of displacement.

But I cant even imagine what that has to do why Vray does start the rendering after 15 minutes.
Imagine this in an animation.horrible.

Also there are no indications in the statusbar or VFB what is happening in those 15 minutes.

I have to stress out that iam not even an usual user of Vray. Iam a completely nerd and know a lot of things under the hood of Rendering and Vray and coding. But even for me its an extreme hassle with Vray 5. I thought everything will be more easy. Not at all. Its currently horrible for me and I have a lot of employees.

[sirio76]

From what I read it could be a bad displacement setup. Vray displacement is an amazing tool and it’s incredibly efficient, unfortunately if you do not tune that properly it can easily lead to long preparation time, RAM consumption and slow render time. I must add to this that default setting for displacement are not ideal, it could be easily tuned to get a lot more speed, and I really mean a lot! I guess developers decided to set it like that so that it can always produce good detail but as far as efficiency/speed a lot can be done.

[PdZ]

I already said: BEFORE even V-Ray is compiling geometry (which is preparing the displacement), it does not even start the rendering.
But I will test that too. I doubt that is the case however

[deyan.hadzhiev]

Hi PdZ , from what I read, it really sound like the displacement may be the culprit for the long renderstart, while the max transparency level may be the cause for the overall long rendertime.

As sirio76 mentioned, tweaking the quality settings of the displacement may change the preparation time.

I must add to this that default setting for displacement are not ideal

We have also had some internal discussions for the current defaults and we may tweak them in the future to provide better startup and render times while having good quality for most of the scenes.

Last but not least - if the displacement in the scene is located in parts that may not participate in the rendering, changing the geometry generation to "On The Fly" might improve startup time, but it may impact rendertime.

[PdZ]

Thx deyan.hadzhiev I will try that !

[PdZ]

Doesnt help at all. I disabled all displacementtags and also globally. I even deleted almost everything out of the scene. Scene does not start until a long amount of time...

[Doger]

Are any proxies inside the project?

[PdZ]

Yes.
I maybe think to have found what is the culprit. Maybe its my materials are in the network drive also proxies. Maybe V-Ray have to load them before starting rendering and this takes so long. I will check that.

[PdZ]

yeah. Thats it!!!

[PdZ]

NOPE. It was not network or anything else. I DONT KNOW why this is happening...

[deyan.hadzhiev]

Hi PdZ, something caught my attention and it may reveal the cause:

Maybe its my materials are in the network drive also proxies.

Do you have the materials and/or the proxies stored as an asset in a content browser library?

[Doger]

Do you also use VRay Proxies?