[Solved] BlendMat LightMtl + Cscatter = infinite Ram usage

[FrostKiwi]

Hey,
I'm scattering 10000 7k poly mushrooms over a cave model with a BlendMat applied, which fuses a Corona LightMat and a CoronaMtl. (since they have glowy bits and so much of it, that blend makes more sense then self Illumination)
Using the BlendMtl on an instance results in massive "Building Acc. Structure" times and Exponential growth in memory usage.

Demonstrated on AO pass and only 1000 for faster results:

Long story short:
Using just simply CoronaMtl on Mushroom with textures and everythin: 4secs "Building Acc. Structure" ~50mb ram usage
Using LightMtl: 5secs "Building Acc. Structure" ~50mb ram usage
Using BlentMtl to Blend Light and CoronaMtl: 2min. "Building Acc. Structure" ~10gb (10000mb) ram usage

If I do 10000 instances my PC just suicides and I need to terminate 3dsmax in the hopes Taskmanager actually opens.
-projected "Building Acc. Structure" time 20 mins and 100gb ram usage

Keep in mind:
Parsing Scene always just takes under a second, "Building Acc. Structure" is also Single threaded, I'm on a fx-8350.

[maru]

You are basically rendering billions of lights. Use self illumination for the mushrooms.

[FrostKiwi]

You are basically rendering billions of lights. Use self illumination for the mushrooms.

ohh, you are right :|
Didn't think that was the source, since using just LightMtl didnt make it worse...

[Ondra]

yup, basically if you use true light emission, instancing has to be disabled. This is why we have self-illumination