Huge delay until V-Ray starts to render. Why?

[Helldoor]

Hi there,

I'm currently working on a big project with lots of buildngs (surfaces/solids/blocks), trees (proxies) and grassed areas (V-Ray fur). The file size is about 800 MB. It's a project I started working on in 2016 and where I had to import lots of 2D and 3D exchange files into (CAD floor plans, 3D buildings etc). I do everything I can to declutter the file and erase everything I really don't need for my current rendering. The "_purge" command I use daily. But still, whenever I click the render button - no matter what kind of resolution or detail level I use - it takes a couple of minutes until V-Ray starts compiling the geometry. During this time, Rhino is not really responding? After the rendering has begun, the 'compiling geometry' and 'light cache' passes take pretty long, the prepasses and the render however are very fast. Under these circumstances is the usage V-Ray RT unthinkable...
Any idea, what causes such a behaviour? Is it the grass-areas with V-Ray fur? Or maybe the blocks? Any tips on how to cope with the ussue or purge the file any better?

Thanks in advance!
Hell

Edit: I have enough RAM (64GB) and not even a quarter of it is used, before starting to render...

[georgi.georgiev]

Hi,

There is a known issues when rendering ortho cameras and there is a material with displacement in the scene, Normal Displacement more specifically. Changing the Mode / Map parameter to 2D Displacement resolves the issue.

Regardless, please be informed that, depending on the complexity of the project and the assets related to it, the bootstrap phase could take considerable amount of time. If V-Ray Fur has been used extensively throughout the project, generating the geometry at render-time will also prolong the process. Furthermore, if the GPU render engine is used, the first time a render is initiated, the CUDA API needs to be compiled and this extends the render time as well.

If you could share the project with us, we could further investigate the behavior and possibly provide a workaround. If deemed necessary, please send us an archived copy (V-Ray > Pack Project) via email or a file-sharing service of your choice to support@chaosgroup.com

[Helldoor]

Hi Georgi,

thanks for the quick answer!

I will check for any materials with Normal Displacement. As I said - I began working on this project three years ago, in Rhino 5 with V-Ray 2 and meanwhile it is a bit of a pain in the ass to work with... And I don't know why, but everytime when I save the file, I see messages about the textures being packed, in Rhino's command field - something, I've never seen in my other projects.
However, I'd gladly pack the model and send it to you via WeTransfer. It would be really awesome, if You could really take a look at it and give me feedback or a workaround!
Thanks in advance!

[Helldoor]

Hi Georgi,

I've just uploaded the packed model to WeTransfer. It's pretty big - 1,2 GB, but considering the average Internet speed in Sofia, downloading it shouldn't take that long.
I thanks You in advance for taking a look in the model and am looking forward to hearing from You.

Have a great day!
Best regards
Helldoor