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Author Topic: Instancing  (Read 883 times)

Rokas

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Instancing
« on: November 20, 2014, 07:22:09 PM »
I wonder what is this "instancing" iToo developers keep referencing, since so many actions break it.
Is it really bad if we break it, can we do it in some cases, in what cases this is not recommended, when must be avoided, when it is ok... etc

How can I test to see what what my style loses by not using instancing?

I tried this:

This is 100m x 100m plane with floor style applied and a teapot of course, scene would not be complete without a teapot.
Full Instancing at work:
scene file size: 0.5 M
render time 16s.
Full render: time from click to responsive max: 28s


Floor collapsed to editable poly:
Instancing lost:
Scene file size: 68.7MB
render time: 13s
Full render: time from click to responsive max:  18s


Floor collapsed to multiple editable poly via railclone tools:
Instancing lost:
No Items: 42190
Scene file size: 88.4 MB
render time: 18s
Full render: time from click to responsive max: 12m:48



My conclusions so far:
> Once collapsed,- you can't edit your parameters,- you must be happy with result. Fair enough, good enough.
> Viewport performance is lost- well i can use boxed mode, but i like Point-Cloud (mostly often for complex scenes) Though Point-Cloud too not always work on nested segments.
> FileSize increases, but i see no problem here. Xrefs are my best friends since long time ago.
> You lose texture mapping- so check that after collapsing.
> I did not monitor RAM usage, but seems it was constant throughout those 3 tests (not sure)

Any other aspect we should be aware of?

Please contribute to this.
« Last Edit: November 20, 2014, 08:10:09 PM by Rokas »

iToo

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Re: Instancing
« Reply #1 on: November 21, 2014, 10:06:36 AM »
That is an interesting question. Basically an instanced segment is as using a VRayProxy for that segment.
As you pointed out, there is not benefit for low poly geometries, but there is a large difference when using high poly geometries.

I've attached a sample scene which i use as stress test. In this case there is no way to convert to poly, because the huge number of faces generated. Instead it renders without problems in RailClone. Also an additional benefit of RC in V-Ray, is that geometry which cannot be instanced, is generated dinamically when needed (when raytracer hits the bucket).

To known the instancing efficiency of a RC object, you can enable Display->Debug Mode, which renders with a specific Material ID the instanced segments.
« Last Edit: November 21, 2014, 05:30:19 PM by iToo »
Carlos Quintero
iToo Software