Very large distances and splotches

[airstyle]

Hey guys, just trying to sus out a GI pickle I'm having -

I've got a very simple scene with a corridor that spans 3km(yes 3 kilometres), and none of the unbiased GI solutions are rendering it without splotches.

Currently using Brute force for Primary - I have tried LC and IR for secondary and haven't had any luck removing splotches. Using brute force for secondary works without splotches but obviously results in a ridiculous render time. Might have to spend a day working with QMC/DMC settings to get it right.

All surfaces are solid (about a metre in thickness) and are all intersecting. There is one giant vray light spanning from the start to end of room - using 10 smaller lights doesn't change the splotch issue either.

Cheers, grey render attached - splotches are towards the end of the corridor.
Greg.

[Roest]

If you use LC you've tried both screen and world?

to add:
Is your object subdivided properly?
If it is one object you could try cutting it in pieces.

[airstyle]

Roest, yes I've tried both, world settings result in alot of smaller splotches, even with lots of filtering on. Though I'm not an expert on LC filtering so I might be missing something.

Yes it's more than adequately subdivided, but no I haven't tried cutting into smaller pieces - good idea cheers .

[Da_elf]

is it a still, an anim?
have you tried calculating irradiance and lightcache at various intervals along the corridore and adding them together?

[airstyle]

Da_Elf, I think you've just solved the problem (theoretically). Haven't got time to test it out but I think your logic is spot on. Let's hope v-ray thinks so too . Cheers guys