Luxcoreui render resolution changing

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Fox
Posts: 44
Joined: Sat Mar 31, 2018 11:17 am

Luxcoreui render resolution changing

Post by Fox » Sat Aug 11, 2018 12:34 pm

Has anyone noticed this when you go to change film render resolution in luxcore ui, then sometimes it wont change and will be stuck there, memory and CPU use gets very low.

More often it will happen when environment is homogeneous volume with multiscattering off, almost never with heterogeneous volume and multiscattering on. Homogeneous volume with multiscattering on i have not tested because it's too slow (just won't find sun lamp at all).

Going crazy with this option below will guarantee the resolution change fail:
light.maxdepth =
path.maxdepth =
path.russianroulette.depth =
path.russianroulette.cap =

But homogeneous volume with multiscattering off is even more troublesome. Even when you get to change resolution and render works for a half day, next day you can find 1-2 CPU cores work, memory use is only half and given you have film.safesave and film.outputs.safesave enabled you can see the backup files are identical in size to the new files.

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Dade
Developer
Posts: 1336
Joined: Mon Dec 04, 2017 8:36 pm

Re: Luxcoreui render resolution changing

Post by Dade » Sat Aug 11, 2018 6:17 pm

Fox wrote:
Sat Aug 11, 2018 12:34 pm
Has anyone noticed this when you go to change film render resolution in luxcore ui, then sometimes it wont change and will be stuck there, memory and CPU use gets very low.

More often it will happen when environment is homogeneous volume with multiscattering off, almost never with heterogeneous volume and multiscattering on. Homogeneous volume with multiscattering on i have not tested because it's too slow (just won't find sun lamp at all).

Going crazy with this option below will guarantee the resolution change fail:
light.maxdepth =
path.maxdepth =
path.russianroulette.depth =
path.russianroulette.cap =

But homogeneous volume with multiscattering off is even more troublesome. Even when you get to change resolution and render works for a half day, next day you can find 1-2 CPU cores work, memory use is only half and given you have film.safesave and film.outputs.safesave enabled you can see the backup files are identical in size to the new files.
Many years ago I solved a problem in old Lux where the software was stuck while tracing a ray over an endless loop because, some time, with 32bit floating points, t + a = t (so instead of progressing over a ray and reaching the end, it was never moving forward). This can happen for large values of "t", small values of "a", etc.

It sounds like the same case. However, I need a scene a test scene to try to reproduce and investigate the problem.
Support LuxCoreRender project with salts and bounties

Fox
Posts: 44
Joined: Sat Mar 31, 2018 11:17 am

Re: Luxcoreui render resolution changing

Post by Fox » Sat Aug 11, 2018 10:05 pm

I was unsuccessful to replicate this issue today.
It happened last with huge scene (60 meters, 400M triangles) and BidirVMcpu + MLT.
The windows had architectural glass enabled, there were hemi hdr, sun and 1 point lamp.

One thing though, in homogeneous volume with multiscattering off, point lamp is not directly visible through Glossy Translucent lamp shade to camera.

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