Exporter, does not save Emissive Factor/Emission Strength Value for materials.

Currently the Emissive Factor/Emission Strength is not exported to the .glb file.

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Steps to Reproduce:

Following this example

I set up a material using the Principal BSDF and Emission nodes. I then make some adjustments to the Principal and Emission settings to get something looking like this scene.

The nodes on each material look like this.

After exporting an re-importing I get this. imported nodes

I wasn’t sure if it was the import process or the export process so I checked the .glb embedded file. It appears the emissiveFactor portion is always being saved as 1, 1, 1 (see below)

"emissiveFactor" : [
                1,
                1,
                1
            ]

Knowing that the Emissive Factor is supposed to be an RGB value I also tried attaching an RGB node and attaching it to the strength of the Emission node, however it was still not saved.

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Additional Notes:

I also went in and edited the “emissiveFactor” in the embedded .glb file. Like so…

"emissiveFactor" : [
                0.33,
                0.33,
                0.33
            ]

When importing this edited file, I get a node tree including a multiply node. Where the Color2 of the multiply node matched my edited .glb file.

The result looks okay, but is too bright since it still takes into account the emission node’s strength. (Which is always set to 1.0)

Upon exporting this new scene the emissiveFactor is still not saved.

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Using Blender 2.8 Beta Windows 64 bit, March 18th, 19:10:14 build.

Edit: updated example link

[emackey]

@Taroslord, re: Principled BSDF. You’re looking at the manual for 2.80. Check the manual for 2.90 instead. It doesn’t show a picture, but the first sentence says it should work with the Principled BSDF node. It should be supported since 2.82.

[Taroslord]

Thank you for your answers. The only way to export emission textures from Blender to glb is to use the official way, that is described in this image and is found in the manual: https://docs.blender.org/manual/en/2.80/_images/addons_io-gltf2_material-emissive.png

It works, but the problem of this solution: It doesn’t support the emission slot inside the principled shader node in Blender. This would be a clean solution in my point of view.