LuxCoreRender Forums

I had this problem in the past once, but with the old LuxRender. In that case it was that I had created an interior surface in one of my lenses, which somehow caused this behaviour. I will have a look into your blend file if I find something like that

B.Y.O.B. wrote: ↑Sun Jun 16, 2019 1:04 pm Have you checked if all your interior/exterior volumes are set up correctly? Especially check the camera volume. Usually this is the problem.

I think it's correct, the camera is set to the same volume of the fog cube it is placed in.

CodeHD wrote: ↑Sun Jun 16, 2019 1:07 pm I will have a look into your blend file if I find something like that

Thanks!

You didn't set the world volume

Ok but why is a world volume needed when there is a cube (003) with a volume for that reason ?
The world volume renders way slower than the cube.003 volume.

Indeed, I hadn't even noticed that setup, went so quick to it that I ddin't leave camera view

It seems the mirror picks up the wrong exterior volume. If I set that explicitely, I don't need the world volume. In fact, it appears to render much faster because there is less volume.

Ah ok so I need to set the mirror to the proper ext. volume, thanks for that tip!

I used one of the files provided above (derived from "cold fusion" by SharlyBG), so those may contain this error too!

epilectrolytics wrote: ↑Sun Jun 16, 2019 1:23 pm Ah ok so I need to set the mirror to the proper ext. volume, thanks for that tip!

I used one of the files provided above (derived from "cold fusion" by SharlyBG), so those may contain this error too!

There are several files in the cold fusion thread. The one that a played with, also had extra light source as flat world color. This might not be visible to camera depending how you change the scattering cube normals, volumes and materials.

CodeHD wrote: ↑Sun Jun 16, 2019 9:18 am

kintuX wrote: ↑Sat Jun 15, 2019 10:11 am Took time to go into to details. Yes, scene is an abomination for pro-creativity
After couple of hours analyzing & diagnosing all posible variations i found it!!! GOT NOTHING TO DO WITH VOLUMES !!!.
It's the freakin' laser beam! Sometimes it shows as visible, but sometimes not. Depending on angle, wattage and efficacy, such a glitch can occur.

Today, I played around again with this as well (hadn't followed the details of this thread very well teh last few days), and after installing the new 2.2beta2.

I see the same glitch, and it also appears to be conencted to the laser beam size, and the camera axis. Based on what I see, I also believe it to be caused by the light-rays rather than the camera rays. For very wide lasers, the direct beam appears to decay quickly. After another object (e.g. a glass lens), the "decayed" suddenly reappears at a mor realistic intensity. The dark band may still appear, depending on how the beam is being focused.

I have made a simple file to show the problem. I can open a GitHub issue as well.

In my example, i disabled volumes altogether that's when i noticed it. And i kinda like to see laser beams without having to resort to volumetrics. Love the little bastard Don't wanna see it disappear. Why i'm also in doubt now: If laser beam being visible without volume is a part of the problem, i don't like solving it.

kintuX wrote: ↑Sun Jun 16, 2019 9:33 pm In my example, i disabled volumes altogether that's when i noticed it. And i kinda like to see laser beams without having to resort to volumetrics. Love the little bastard Don't wanna see it disappear. Why i'm also in doubt now: If laser beam being visible without volume is a part of the problem, i don't like solving it.

I don't know really what you did, cause you didn't supply a blend file with that post from Saturday where you concluded that it's got nothing to do with volumes. That gif you showed looks to me like a) there is still some volumetric stuff going on (fireflies in the background), and also the beams are tilted and shining towards the floor, which is where you get the "rainbows". None of that happened in the blend file you posted some time before. If I disable all volumes, everything is really black.
Laser beams without volumetrics shouldn't be possible with the current features.

CodeHD wrote: ↑Mon Jun 17, 2019 10:14 am

kintuX wrote: ↑Sun Jun 16, 2019 9:33 pm In my example, i disabled volumes altogether

If I disable all volumes, everything is really black.
Laser beams without volumetrics shouldn't be possible with the current features.

@kintuX, are you sure? One object in the scene with a material with a homo- or heterogeneous volume with scattering>0.000 is enough to get some scattered light even if all other materials have clear volumes defined one material has a homo/hetero external volume. The effect might be small but its there and visible.

@CodeHD, what else did you expect? If there is nothing scattering (e.g. matte, roughness, translucent, homo/hetero volume) the scene keeps black with the exception of direct light. But the latter is another story. There is no way to see ever any beam from any but direct angle in perfect vacuum. And direct means blinding depending on ‚contact‘ radius of the beam. If the surface of hitting beam covered one pixel only and intensity was only in the range of sensors sensitivity then you got one single point on your image (assuming perfect clear optics).