How to change gltf/PbrMetallicRoughness default Blend Mode to transparent ?

[ThanosRestas]

Any input on how to do this will be deeply appreciated

[atteneder]

Can you elaborate in what kind of workflow you'd want transparent to be default?

I'm asking because:

• For the classical glTF import workflow (design- and run-time) the glTF material dictates the blend mode anyways
• For manually creating materials with that shader Opaque makes much more sense as default. Also, why would you want to manually use these Shaders?

Thanks for your input

[ThanosRestas]

Thanks for the reply ! So:

Can you elaborate in what kind of workflow you'd want transparent to be default?

I want the transparency of the transparent textures to be visible on the glTF models I load.

For the classical glTF import workflow (design- and run-time) the glTF material dictates the blend mode anyways

What I'm basically asking is how to edit this glTF material so it comes as transparent by default.

For manually creating materials with that shader Opaque makes much more sense as default. Also, why would you want to manually use these Shaders?

I don't want to edit them manually(via the editor or whatever). I would like to find how you are generating this material so I can change its blend mode to transparent via code at time of the model's instantiation. Like how would the Blend Mode parameter just be set to transparent ?

Obviously I'm just starting to learn about how materials/shaders are created and applied so probably I'm confusing you a bit. Might be something I'm missing in understanding your code too.

[atteneder]

Alright, got you. I'll create a new answer.

[atteneder]

glTF comes with out-of-the box support for:

• Opaque materials
• Alpha Masking (equivalent to Blend Mode Cutout)
• Alpha Blending (equivalent to Blend Mode Fade)

That does not allow you to re-create materials like transparent glass, where light transmits, but there's still a specular reflection.

To achieve this, you have to make use of the KHR_materials_transmission extension. It allows you to create glass-like materials (even tinted or frosted ones). The shader's blend mode will implicitly be set to transparent if you use this extension. Make sure your glTF generator has proper support for it.

Note: Depending on your render pipeline (settings), glTFast only offers partial support for transmission. See #111 as well.