After switching RGB -> Temperature-> RGB scene went black

[johndow16]

Hello,

A very strange issue. I have a scene with a few area lights. I selected one of those lights, changed it from RGB to Temperature, tried some values and then switched back to RGB and the scene went black and now nothing works. I mean it doesn't matter what I do, everything stays black when I use LuxCoreRender in that scene. I tried deleting all lights, switching renders, changing settings, adding lights, etc. but without any luck. On one occasion I was able to get it back to work, but the scene was all pink and then Blender crashed. Here is what it looks like:

Here are two crash reports:

Lighting_test_01d_LuxCore.crash.txt Lighting_test_01d_LuxCore_5740_autosave.crash.txt

Windows 10 x64 (2004 19041.867) Blender 2.92 BlendLuxCore v2.5RC1 GTX1660 (465.89)

[Theverat]

Can you upload the scene, or a simplified version of it that still shows the issue?

[johndow16]

Yes, here is the scene:

LuxCore_Upload.zip

[foreachthing]

First issue I see here, is that your camera is nowhere close to your building. Let alone inside. Second (this might be only because it was packed), I had to redo all the textures because the images where missing (all pink).

I started a new blend and appended all your objects, materials and textures from your .blend. Still, the textures where not working. I've imported some images/textures and got this:

Warnings are about the "poster back". No crashes, though.

[johndow16]

The scene was way too big for upload, so I had to clean it up (remove a lot of elements and move everything closer to the center). Because the viewport was black I couldn't see the textures. The camera in the original scene was animated and that's why when you switch to it, it shows outside the 'scene' (that was moved).

The textures are there but looks like they are not connected for some reason (even though shader editor shows that the textures are connected).

PS. I downloaded my own zip and tried it - result was still the same - black screen. I tried to change some LuxCore settings and Blender crashed.

LuxCore_Upload.crash.txt

[foreachthing]

Try this anyways:

1. Start Blender with default working settings
2. Switch rendere to LuxCore.
3. Append all your data from your file (Objects, Materials, etc...)
4. Render

This works on my computer.

[johndow16]

This workaround does work, but the question remains: What went wrong in the original scene? 😕

PS. I tried to revive the original scene and I was able to make it work again by changing LuxCore settings (switching between pathtracer and bidir back and forth, enabling and disabling different unrelated options, etc.). But the scene looked as if there was no lights at all (only emissive mats) and then Blender crashed, so I couldn't save it.

[Theverat]

Yes, here is the scene:

LuxCore_Upload.zip

The scene does not render black on my end, but it is very strange in other ways. The meshes are either solid red or blue, and I have no idea where these colors come from. Nothing in their materials indicates they should have these colors. It also seems like they are emitting them, since they have no shading at all. Can you explain why this happens, is this intended?

LuxCore_Upload.crash.txt

The stacktraces in the crash logs you posted look to me like they are caused by a bug in Blender. To get them fixed, you need to make a report on the Blender bug tracker.

[johndow16]

My best guess is that those colors indicate face orientation: blue is the front and red is the back. As I remember, showing front face color (blue) instead of a texture was a feature in older Blender versions. In newer version, when you switch to 'Viewport shading' mode you should only see backface color (red, if show face orientation enabled) and textures/mats on the front facing polygons. I have no idea why you see blue color instead of textures/materials.