IM blotch through glass

[fAEkE]

I get these IM blotches, but only through glass material. The IM is baked with LC. Check the image.

[Neilg]

post your glass & render settings.

[fAEkE]

[zeronove]

what about retrace threshold? ...is it checked or not?

edit 1
ops, too late ...it seems not; I'll try checking it

[Neilg]

try taking the glass off generate/recieve gi. or cast shadows.

also check your normals of the frame - i've seen weird ir map/rendering issues on the back of geometry when seen through glass.

[fAEkE]

The render is fine if I render a single frame with LC+IM. So I guess it's the GI baking thats the issue. I'm trying to pinpoint the problem right now, and to see if retrace treshold can fix it.

[fAEkE]

I made some testrenders yesterday, and it seems that it depends on the amount of animated frames. I tried the same same settings and only used 50 frames out of my 400 frames animation, and then it worked fine. With 400 frames it's still blotchy. Is 5000 LC subdivs not enough?

[Morne]

that is VERY strange. More so since your light cache settings currently are per frame so even if you make it 10 000, it will still be per frame and shouldnt make a difference if your animation is 5 frames long or 1000 frames long

what about doing a IM animation prepass calc instead and then IM render after that?

[fAEkE]

Well, I use Fly-Through with LC. Doesn't LC distribute all samples over the entire animation?

I don't have any more time to troubleshoot

[Neilg]

fly through shares those 5000 samples over the entire animation, so fewer frames = more samples for the same area. try setting it to world mode instead of screen?
5k should be alright for that though.

[super gnu]

one thing to note, flythrough mode seems to distribute the samples along the timeline according to the frame range specified on the 3dsmax timeline.. so even if your camera is only 50 frames long, if your max timeline is set to 5000 frames, then the vast majority of your samples will be bunched up at the end of the path, and the beginning will have very few.

this isnt anywhere in the documentation that ive seen but ive noticed it many times.

[Morne]

yes you didnt mention that it was a file from flythrough mode, or I missed it in your initial intro.