Number of Faces in Vray Proxy Preview Affecting Memory?

[shegmann]

Hi all,

We have a very large scene (70+ million polys at last count) with tons of objects. It's a refinery, lots of buildings, misc. objects, cars, etc. We have a core area that is standard Maya geo, but most of our objects are instances of Vray proxies to help with memory/management, and so forth.

The question I have is... when we create a Vray proxy, one of the options is Faces in Preview. Does this amount affect the memory load or anything else or is it arbitrary?

i.e. I have a group of 100 cars, randomly instanced into a parking lot structure. Group A was created using the default of 10K Faces in preview, so it's 1M polys. Group B was created using 200 Faces in preview, so it's only 20K total. Does this have any impact on the scene? I would expect it does. But before I replace our entire fleet of cars, I thought I'd check.

Many thanks!
Sarah

[stezza]

I would suggest it does count, why not set to bounding box?

[shegmann]

Well that would be because we didn't think of that, ha. Pardon my ignorance, we are somewhat new to the Vray pipeline. However, when I set the VrayMeshPreview Drawing Overrides to LoD: Bounding Box, it's still displaying the mesh in addition to the BB. When I use the shape node, it works. I bring this up because neither the memory used while rendering nor the memory used while opening the scene seem affected by the bounding box vs. mesh preview. The poly count remains unchanged, which does beg the question of will setting the Faces in Preview affect it? I suppose that I can change my proxies and do more tests. Thank you for the suggestion.

[Morbid Angel]

I think loading any kind of data from vray proxy into viewport will eat memory. If you have cache geometry checked in vraymesh options that it will surely load it into ram and worse per frame if its animated.
What I recommend is with each proxy to export a preview geometry and load that instead, there is a second field called viewport preview file which basically loads a proxy preview instead of reading from vray mesh. For cars for example you can make one car proxy and use it across all the cars. Like one for sedans one for suv and so on. For other objects if you can't or don't want to make viewport previews you can just make primitive shapes and use those.

[shegmann]

Ah, so... my unfamiliarity is definitely showing. I think I found the correct place to change to the bounding box, triggered by the suggestion Morbid made. Instead of setting it in the VrayMeshPreview, I set it in the VrayMesh tab, which makes sense once I thought about it. This does affect overall poly count. It... seems to affect the render memory though not the load memory (caching is off). However, I do know that my tests are just using the performance manager and are pretty darn inaccurate. It's the best I've got right now though.

I haven't tested the preview geometry, though that is on my list. I did export new vrmeshes from actual reduced geometry but with the Faces in Preview unchanged. As one might expect, the polys in the scene are unchanged between the two proxies, but the file size for the normal vs. reduced proxy is significantly different, as one might expect. Thank you for your suggestions and help. We'll be continuing to test this. Our render farm has some nodes that are lower in memory than others, so this particular issue is rather important for us for this latest project, not just an esoteric interest in keeping our memory usage low.

[Morbid Angel]

yup while proxies do reduce memory or more like allow to render with lower ram machines you might also want to explore converting your textures to .tx and using those instead.

[shegmann]

Thank you all for your fast and helpful advice. We did a test with proxies made from significantly reduced original models and there were not obvious changes, as one might expect. Its interesting too, because we're seeing a difference of around 8mb per original Vrmesh file down to 500kb with the reduced Vrmeshfile. However, the overall file size and memory usage of the scene is nigh on identical when either set is used. Using the bounding boxes does seem to have improved some memory usage and I'm going to be switching all of proxies over to that rather than testing with our (relatively) fast cars only scene. And we will definitely check out the .tx, I know that one of our issues is the number of materials based on how the proxies were originally made. But that's something we'll be changing for our next refinery project, ha. Thanks again.