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Export GLTF/GLB - 2-nd time in 1 session won't work
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Description

IIntel Core i5 6600K, @3.50 GHz; (RAM) - 32GB
System Type: Win 10 PRO 64 bit
Windows 10 (64Bit), Nvidia GTX 2 x 1050 Ti

Used Blender Version:
Date: 2018-12-05, 02:05
Hash: 1fa527bfa3a
Branch: blender2.8

Export GLTF/GLB - 2-nd time in 1 session won't work

  1. I create a simple cube, I apply a texture to a Principal BSDF shader,
  2. From where I'm exporting the file as GLB file - and it works
  3. I'm trying to repeat the operation by exporting it again /.GLB, and won't work. A error message appearing.


I'm planning to present Blender 2.80 at my company in a higher level management, as tool which we need to consider for a real integration to our pipeline of production /automotive cockpit electronic industry/.
Currently, I've been using Blender since 2011/12, for commercial need for all my daily tasks and needs in the industries I've been working on. Even now in this company I personally use Blender any 3d related task.

For us now the new GLTF/GLB integration is really something we want to try in real, and if you could provide this kind of support, I will be able to present next week some examples in real-time to the team.

Best Regards,
Ivaylo

Event Timeline

Ivaylo Gogov (ivaydesign) triaged this task as Confirmed, High priority.
Ivaylo Gogov (ivaydesign) lowered the priority of this task from Confirmed, High to Normal.Dec 6 2018, 12:48 AM
LazyDodo (LazyDodo) raised the priority of this task from Normal to Needs Triage by Developer.

please do not assign priority your self, since it actually makes it less likely for the people triaging the bug tracker to look at your report.

@Ivaylo Gogov (ivaydesign) In the past few days there have been major improvements to the export settings, but unfortunately a serious bug has crept in with the "Save Settings" feature. I believe this will be fixed in the next few days.

As a workaround, on your broken Blender project, go to the "Scene" properties tab, expand the "Custom Properties" section, and delete a custom property named glTF2ExportSettings. Then you should be able to export again, but, don't save the export settings until after this is fixed.

Upstream issue tracker for this is here: https://github.com/KhronosGroup/glTF-Blender-IO/issues/148

Hello guys,
Do you know is there is a chance of exporting shaders information in form of .GLSL/fragment, vertex shaders./ from Blender?

@Ivaylo Gogov (ivaydesign) glTF version 2.0 does not ship with raw shaders, as they are not very portable between different platforms (WebGL, OpenGL, Vulkan, Direct3D, Metal...). Often a shader is very deeply paired with the inner workings of the particular rendering engine it's used by, and can't meaningfully move between engines even on the same platform. glTF 1.0 had WebGL shaders and was tied specifically to the WebGL platform for this reason, but in glTF 2.0 the shaders have gone away, replaced by PBR (Physically Based Rendering) and a set of well-defined texture maps that enable a wide range of physically plausible materials. Thus, glTF 2.0 enjoys platform-independence and engine-independence.

This presentation contains a description of the glTF 2.0 PBR material system: https://www.khronos.org/assets/uploads/developers/library/2017-gtc/glTF-2.0-and-PBR-GTC_May17.pdf

There's an overview on page 9, followed by a deep-dive on the remaining slides.

Long story short, glTF 2.0 supports: Base color (albedo), Normal map (tangent-space), metallic, roughness, occlusion (pre-baked), and emissive. Of these, "occlusion" is not yet supported in this exporter, but the rest can be determined by looking for image nodes hooked up to the Blender Principled BSDF node, and the Emissive BSDF node.