Wrong transparent node setup in GLTF import #63489

New Issue

nurbson · 2019-04-11T12:33:00+02:00

nurbson commented

2019-04-11 12:33:00 +02:00

System Information
Operating system: Linux and Windows
Graphics card: NVidia GTX 1060 6GB

Blender Version
Broken: 2.80, a3b88c917299, 2019-04-10

Short description of error
The GLFT/GLB importer has wrong transparency factor on transparent materials for Transparent BSDF

Exact steps for others to reproduce the error
My usecase is a bit more complex since I generate my glb files from a threejs scene. But steps to reproduce are:

create an object3D in threejs with this material

MeshStandardMaterial( {
          color: new THREE.Color(0xDDDDDD),
          transparent: true,
          opacity: 0.2,
          shininess: 10000,
          transparencyMode: 2
      })

export a glb file
open a new scene in blender 2.80
import the glb

The material nodes are setup correctly but the factor for the mix shader should take the opacity value of the glb material for the transparent BSDF node.

**System Information** Operating system: Linux and Windows Graphics card: NVidia GTX 1060 6GB **Blender Version** Broken: 2.80, a3b88c917299, 2019-04-10 **Short description of error** The GLFT/GLB importer has wrong transparency factor on transparent materials for Transparent BSDF **Exact steps for others to reproduce the error** My usecase is a bit more complex since I generate my glb files from a threejs scene. But steps to reproduce are: - create an object3D in threejs with this material ``` MeshStandardMaterial( { color: new THREE.Color(0xDDDDDD), transparent: true, opacity: 0.2, shininess: 10000, transparencyMode: 2 }) ``` - export a glb file - open a new scene in blender 2.80 - import the glb The material nodes are setup correctly but the factor for the mix shader should take the opacity value of the glb material for the transparent BSDF node. ![imported.png](https://archive.blender.org/developer/F6930783/imported.png) ![correct.png](https://archive.blender.org/developer/F6930787/correct.png)

nurbson commented

2019-04-11 12:33:00 +02:00

Added subscriber: @nurbson

Julien Duroure was assigned by Brecht Van Lommel

2019-04-11 12:35:35 +02:00

Brecht Van Lommel commented

2019-04-11 12:36:12 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2019-04-11 12:36:12 +02:00

Please attach the .glb file to reproduce the issue.

nurbson commented

2019-04-11 12:59:06 +02:00

Here is the glb. You need to scale it to 0.01 after import since our measurement in the threejs scene is in cm, not meters.
Besides: The UV maps are messed up, too. But I'm still trying to find our where the problem is.

schrank (3).glb

Here is the glb. You need to scale it to 0.01 after import since our measurement in the threejs scene is in cm, not meters. Besides: The UV maps are messed up, too. But I'm still trying to find our where the problem is. [schrank (3).glb](https://archive.blender.org/developer/F6930818/schrank__3_.glb)

Julien Duroure commented

2019-04-11 20:47:44 +02:00

Discussion will take place in upstream issue tracker:
https://github.com/KhronosGroup/glTF-Blender-IO/issues/424

Discussion will take place in upstream issue tracker: https://github.com/KhronosGroup/glTF-Blender-IO/issues/424

Julien Duroure commented

2019-04-15 11:38:59 +02:00

I not agree with the analysis.
Factor of the mixShader node will do the following : 1 for transparent, 0 for opaque.
The Add node is used as factor. So if you have an alpha of 0.2, you have to set factor to 0.8.
The second image is wrong, because add 0.8 and 0.2 --> full transparent because of factor of 1.0

I not agree with the analysis. Factor of the mixShader node will do the following : 1 for transparent, 0 for opaque. The Add node is used as factor. So if you have an alpha of 0.2, you have to set factor to 0.8. The second image is wrong, because add 0.8 and 0.2 --> full transparent because of factor of 1.0

Bastien Montagne commented

2019-05-16 11:18:49 +02:00

Added subscriber: @mont29

Bastien Montagne commented

2019-05-16 11:18:49 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2019-05-16 11:18:49 +02:00

Bastien Montagne commented

2019-05-16 11:18:49 +02:00

Note that Principled shader now has an Alpha value too…

Anyway, More than a week without reply or activity. Due to the policy of the tracker archiving for until required info/data are provided.

Note that Principled shader now has an Alpha value too… Anyway, More than a week without reply or activity. Due to the policy of the tracker archiving for until required info/data are provided.

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Wrong transparent node setup in GLTF import #63489