Do Indigo/Blendigo support custom vertex normals ?

General questions about Indigo, the scene format, rendering etc...
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Headroom
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Do Indigo/Blendigo support custom vertex normals ?

Post by Headroom » Thu Mar 04, 2021 1:06 am

I am not sure whether or not this needs to be supported in Blendigo and Indigo.
CAD models, when exported as .obj contain custom vertex normals (custom split vertex normals in Blender).
This helps reducing render artifacts and can only be worked around to a degree by exporting models with very high polygon counts.

The model in the images below has 21k faces/triangles. The images were created in LuxCore, which only started supporting custom split vertex normals with the latest 2.4 release.

The 1st image is based on a .obj, which includes custom split vertex normals, the second image is based on a .stl without custom vertex normals. The differnce is pretty clear.
When exported from Blender with Blendigo and then rendered in Indigo the result is the same as the second image, regardless whether I render the .obj or .stl.
OBJ with vertex normals.jpg
STL without vertex normals.jpg

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schwungsau
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by schwungsau » Sat Mar 27, 2021 2:52 am

it should. if you flip normals, refraction will look odd.

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schwungsau
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by schwungsau » Sat Mar 27, 2021 2:54 am

but i think the normal has to be on points instead of vertex......

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Headroom
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by Headroom » Sat Mar 27, 2021 3:49 am

When imported geometry has custom vertex normals, the Object Data Panel in Blender will allow you to clear the Custom Split Normals Data. Otherwise you can add that data. The imported .obj does have custom (split) vertex normals, as expected. The .stl does not, also as expected.

In LuxCore render the results of the .obj and the .stl are what you see in the images. LuxCore render only supports custom vertex normals since the latest release. With Blendigo/Indigo the results for both, .stl. and .obj look the same and look like the 2nd image.

That indicates to me that there is no support for Custom Vertex Normals in Blendigo/Indigo abd unfortunately it "renders" Blendigo/Indigo" as somewhat useless for rendering geometry created originally in CAD software.


I appreciate your response, but I really had hoped for a response from the developers as only they can provide accurate feedback. It is rather disappointing that after more then 3 weeks I don't see any response from the developers.

burnin
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by burnin » Sat Mar 27, 2021 11:07 am

Maybe you should post an issue on Github: https://github.com/glaretechnologies/blendigo

And I fully concur with you, thinking more users & coders should drop by, sharing pros & cons from their experience, cuz it's an amazing engine (HQ oriented, predictive, capable of proper, scientific, light transport simulation, a kind of which Blender lacks. LuxCore is amazing, but too simplified and cut down in some parts.
After getting more exposure, hopefully devs, see the potential in Blender's user base and do something to better the situation instead of just offering a 'good enough' exporter.

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schwungsau
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by schwungsau » Sat Mar 27, 2021 1:16 pm

anyway how did you find luxcore speedwise ?

burnin
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by burnin » Sun Mar 28, 2021 6:18 am

Hm, that's quite relative and subjective issue. Also, speed isn't my priority.

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pixie
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by pixie » Sun Mar 28, 2021 8:40 pm

Do you mind sharing your scene?

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Headroom
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Re: Do Indigo/Blendigo support custom vertex normals ?

Post by Headroom » Thu Apr 15, 2021 3:38 am

@pixie, what format do you want this in ?

The original file is in Blender, but I use an external material for the glass ( Lead Crystal form the material DB) and an HDRI for some of the illumination.
I cannot pack these into the Blender file, but can "ship" those with the Blender file, then you'll have to adjusts paths.
I can also send you the Indigo Scene file, but then you can only render one version of the model.
There are three different "models" in the Blender file.
1. Standard Resolution .obj this includes custom split vertex normals, and should provide better render results in Indigo, but does not
2. Standard resolution .stl. This doe not include custom vertex normals and looks exatly like the result rendered in LusxCore
3. High res .stl. This has its own problems and it looks like there is nor normal smoothing.

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