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Author Topic: forest pro and memory consuption  (Read 1241 times)

MH4288

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forest pro and memory consuption
« on: August 06, 2014, 12:49:33 PM »
Hi,

I wanna ask on few questins about forest and memory:

1. Is it makes a difference when use vrayproxy or regular objects?
2. Is it better poly object or mesh objects? Or it doesnt metter?
3. When I have a very large scale of high-poly grass and put a forest with high-poly trees and so on, it consumed big amount of memory. I dont know why, when I use only say 10 different objects. Is there anything I can do? I use patches of grass made with forest pro and then use it for large scale, but still consumed big amount of memory.

Thanks for answer.

iToo

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Re: forest pro and memory consuption
« Reply #1 on: August 06, 2014, 01:12:08 PM »
Hi,

Quote
1. Is it makes a difference when use vrayproxy or regular objects?

There is little difference. As general rule, we suggest to use regular objects. You can find a detailed explanation here.

Quote
2. Is it better poly object or mesh objects? Or it doesnt metter?

It doesn't matter. Internally all geometry objects are converted to the same format.

Quote
3. When I have a very large scale of high-poly grass and put a forest with high-poly trees and so on, it consumed big amount of memory. I dont know why, when I use only say 10 different objects. Is there anything I can do? I use patches of grass made with forest pro and then use it for large scale, but still consumed big amount of memory.

Really the memory used by Forest should not be high, since it only keeps one instance by model, together the data required for scattering. A different issue is the memory required by V-Ray to render the scene.
Is there any difference generating and rendering a smaller grass area ?

Carlos Quintero
iToo Software

MH4288

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Re: forest pro and memory consuption
« Reply #2 on: August 06, 2014, 02:19:12 PM »
Its a big scene, with some houses, cars and so on, so really hard to tell now. There is maybe 20 different forest pack objects with several meshes/vray proxy each. But maybe its because lots of textures and vray itself.

But still, its better use grass patches to distribute it on large scale planes. But why, when I have let say 10 different blades of grass and every each are very simple and forest uses instancing? I can distribute it as trilions blades, why patches are better?

iToo

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Re: forest pro and memory consuption
« Reply #3 on: August 06, 2014, 05:33:45 PM »
Basically patches are better for large areas because there is a limit in the number of instanced objects. Over 5 mill. items (roughly), performance hit may be significative both in Forest and VRay, and a medium size area using single blades may exceed by far this number.
Carlos Quintero
iToo Software

MH4288

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Re: forest pro and memory consuption
« Reply #4 on: August 17, 2014, 03:41:30 PM »
I made one test now and have a question.

Made a simple grass with about 5 grass objects and scatter it on a land. With 270 000 objects, memory consumption on rendering for 3ds max was 2,8 GB. With 110 000 objects (only distribution scale and threshold was changed) was 1,6 GB. I think its a big difference, why is that? Used same objects, same land, same scene, so dont know why is that.

iToo

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Re: forest pro and memory consuption
« Reply #5 on: August 17, 2014, 06:12:15 PM »
Sorry, but this question should be for ChaosGroup. We don't know how VRay handles internally the memory. Regarding Forest, it takes little memory (less than 100 Mb. for each 100K items).

If that helps, a simple test using Daisy 01 preset takes here about 2.4 Gb. for 250K items, and 2.0 Gb. for 110K items, rendering with Irradiance Map+Light Cache. Using Brute Force instead Light Cache (which usually requires more memory), doesn't go above 2.0 Gb. in both cases.
Carlos Quintero
iToo Software