Viewport Subdivisions results in Full RAM

[vfx_film_televsion]

Hey Chaosgroup-Team and Forum-Members!

I do struggle in rendering one of our scenes. As soon as I turn division levels on my meshes to 0 or higher it takes up the full RAM (64 GB) and additional 20 GB SWAP and Maya Crahes. The meshes are just planes and the whole scene contains about 140 k faces(with smooth preview on), so it seems to me like a bug. I loaded the default render settings and the one thing I changed was to turn on the checkbox for "VIewport Subdivision" in order to produce the error. As soon as I hit render, "Compiling geometry..." continues as long as the RAM is filled up.

If I start a fresh scene, I tried to duplicate planes with up to 7 millionen faces and it rendered in an instant. Any idea why this particular scene won't render ?

Scene file:

https://we.tl/Q6GfJRpQER


Working environment:

CentOS Linux 7
Maya 2018.3
Vray 3.60.04
for API version: 20180000

Kind regards
Pirmin

[vfx_film_televsion]

I think I found the problem, however it does not make any sense to me. I was able to render "smooth" planes with tuning down the Max Subdivs and disabling Tight Bounds under the Settings->Default displacement and subdivisions tab. I thought these settings work only in combination with subdivide and displacement controls on geoemetry nodes. I never had any problems with such excessive RAM consumption of smooth surfaces, so I don't know if the developers wanna have a quick look at the scene file. Maybe there is something fishy going on.

Kind regards
Pirmin

[yolov]

By default subdivision and displacement is view dependent and it might so happen that the default settings are too high and/or there's too much subdiv geometry too close to the camera. Ideally, you can globally reduce the max subdivs in settings > default displacement and subdivision to limit the number of subdivisions V-Ray will do on the geometry.
In V-Ray these settings apply to the viewport subdivisions as well.