Search found 234 matches

by lighting_freak
Mon Nov 30, 2020 2:06 pm
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hello all, You would certainly have to play with the anisotropy of the volume scattering to get this effect. I don't believe that we have to use anisotrophy settings. The material is a molding compound, no directional dependency is expected if you do some real parts from it. the thickness of the mat...
by lighting_freak
Fri Nov 27, 2020 7:07 am
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

HI, sure I can try to describe the meaning: Let's start with "8N" - it is the clear basic PMMA material. The "DF_XX" is the density of light diffusing elements within this basic acrylic. The higher this number the more diffuse the volume is. There are some images that show some k...
by lighting_freak
Thu Nov 26, 2020 8:40 pm
Forum: User Support
Topic: wrong luminance calculation
Replies: 3
Views: 2395

Re: wrong luminance calculation

Hi, I'm quoting myself: Can the above issue be fixed? Please fix this bug that the created light output fits to real world data. One more question to light sources: If one use a 90° spread angle - the surface will emit light like a perfect lambertian emitter? It follows the Cosine-Law? If the spread...
by lighting_freak
Thu Nov 26, 2020 8:26 pm
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hello all, finally the sample part that should use the DF23 material. I hope the download-link works: https://www.dropbox.com/t/4OvpV1lyUnVKTr5R Material definiton in that sample is different, compared to the one that we made during the last days. I continue the investigations on the material - the ...
by lighting_freak
Wed Nov 25, 2020 5:17 pm
Forum: User Support
Topic: Specular reflection vs diffuse reflection.
Replies: 24
Views: 15133

Re: Specular reflection vs diffuse reflection.

Hello all, Is there another shader model that would be worth integrating into LuxCore? Yes, there should be an open BRDF/BTDF/BSDF format, that allows users to define the light interaction precisly per incidence angle... I mean something like a theta/phi look up table. Maybe we could use IES files (...
by lighting_freak
Tue Nov 24, 2020 9:39 am
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hi, thanks for your answers. That is not a property of the scattering volume, but of the surface! On this pictures you may see that the sample plate is almost specular: 20201124_095059.jpg 20201124_094949.jpg Anyway I ran tests with different surface settings (rough, matte translucent, bump) and non...
by lighting_freak
Mon Nov 23, 2020 3:46 pm
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hello all, I'm still working on the example file... but the topic remains in my mind and also on my desk. I've continued the investigation of the scatter volume and all the tests I've done share also one irregularity. The render results doesn't look blurry. It always appears like there's a colour fa...
by lighting_freak
Fri Nov 13, 2020 9:02 pm
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hello,
Dade wrote: Fri Nov 13, 2020 4:39 pm You can't with FP32, etc.
You mean it's impossible or it will just last long? I'm not looking quick results but for high realism. Is FP32 floating point precision? I don't get the connection between the precision and this surface/volume issue.

Thanks for your explanation.

BR
by lighting_freak
Fri Nov 13, 2020 2:21 pm
Forum: User Support
Topic: strange behaviour of homogeneous scattering volume
Replies: 17
Views: 8048

Re: strange behaviour of homogeneous scattering volume

Hi Dade, as you see in the image the reduced path length directly leads to a darkening of the material. This material exists in reality. I have a material sample like this directly in front of me. In my project this diffuse volume will be combined with a rough surface. The real part will be lit by a...
by lighting_freak
Fri Nov 13, 2020 7:30 am
Forum: User Support
Topic: wrong luminance calculation
Replies: 3
Views: 2395

Re: wrong luminance calculation

Hello, Let's calculate the factor: 2*pi*(1 - cos(90°/2)) = 1.84030, as well as the ratio of your results: 318310/172966 = 1.84030 :arrow: the same. I don't really understand where this formula is coming from but it seems to cause that trouble. I totally agree. A physics based conversion from Lumen t...