Env. Light Visibility Cache

[Dade]

I tried to replicate the crashes with a basic scene and I cannot get it to completely stuck, but this one does crash:
279_luxcore2.blend

This happens when I add glass in the scene (note that when I added object with glass to new - fully open scene just with hdri, it didn't crash)

EDIT: this one actually does aswell lock up system when I disable cpu in OCL devices. Otherwise just crashes with exception. Both happen at "starting # native threads"

It was a specific constant infinite light problem (i.e. not affecting infinite light and sky2). I should have fixed the problem.

[Dade]

Not happy about the broken rendering region, hopefuly it can be fixed in the future.

As simple work around:

- run a full image rendering and check the log for the suggested radius:

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[LuxCore][0.466] EnvLightVisibilityCache evaluating best radius
[LuxCore][0.621] EnvLightVisibilityCache best cache radius: 2.01994

- explicit use the suggested values (instead of the default 0.0) to disable automatic radius evaluation (i.e. the source of the problem with border rendering).

- border rendering will than work fine.

[Dade]

@B.Y.O.B: what is the default "visibilitymapcache.map.samplecount" in Blender ? The default in LuxCore has changed over time. I noticed, in the scenes posted here, this kind of setup:

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scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.width = 256
scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.height = 128
scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.samplecount = 4

This one is better while requiring exactly the same pre-processing time (but using 4x memory):

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scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.width = 512
scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.height = 256
scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.map.samplecount = 1

It is probably better to set the "visibilitymapcache.map.samplecount" to 1 because, if you have the free memory, it is always better to use an higher map resolution than more samples per pixel.

The later is also the current LuxCore default values.

[B.Y.O.B.]

I have updated the defaults to be the same as in LuxCore.
I started to look into the screenwindow -> subregion issue, but I'm not done with it yet.

[lacilaci]

So I did a quicktest on few scenes this morning. It works, no more crashing and freezing.

I might post some pictures later(away from pc now).
But overall this kinda works.

Several big openings in scene will bring the env.cache map performance down, almost the same as if none vis.map is used, but still better on some areas though.

There are no artifacts that I noticed, however the objects that before had artifacting on them are still sampled way worse than other objects in the scene.

This introduces quite big differences on noise levels in the image, where some objects are clean and some are noisy.

It is far better than the old single map it seems, but still not as good and problem free as portals.

[Dade]

I have added the support for persistent cache file, it works exactly like PhotonGI persistent file. The property to set the file is:

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scene.lights.__WORLD_BACKGROUND_LIGHT__.visibilitymapcache.persistent.file = cache.elv

The file is created if doesn't exist and loaded if it does.

[Dade]

Going to remove single map env. light visibility cache, if anyone has a reason to keep it, speak now or forever hold your peace.

[lacilaci]

Hm, if the single map option will be removed and defaults for env.cache don't need changing (I haven't seen much reason to change the settings)...

Maybe in blender it would make sense to turn it into a simple checkbox in render settings, maybe even give it appropriate name like "autoportals" and tooltip about what it actually is and when to use?

Reason why I'm suggesting name change is that new users will be looking for portal I assume.

Hm, now that I think about it, an appropriate name and the fact that it would be checkbox would make this setting suitable even for world settings, if on visible spot. So that people don't turn it on when not using any hdri/env light.

EDIT:

In one of my scenes I do run out of memory though with the new default map size of 256 for env cache.

[lacilaci]

Is there some threshold for glossy objects with this? very glossy objects render incredibly noisy, pretty much as if no visibility map is used.

single map:

cache:

none map:

the sink is just a plain glossy material no texture nothing special and object has correct normals and clean topology...

[Dade]

Is there some threshold for glossy objects with this? very glossy objects render incredibly noisy, pretty much as if no visibility map is used.

Yes, like PhotonGI, there is a ".visibilitymapcache.visibility.glossinessusagethreshold" to set the glossy threshold.