How to export glTF with texture paint

Question

I am very new to Blender and I am trying to export a model as a glTF file. The model is available on Microsoft 3D Viewer. What I am doing is as follows:

1. Save the model as .glb from Microsoft 3D Viewer
2. Import the file into Blender (v 2.92)
3. Scale up the model
4. Export it as a glTF file

But when I am doing this, the resulting model has no texture. What are the exact steps to replicate the original model (with textures) scaled up and export it as a glTF file?

Original Model (The way I want it):

Actual Output:

The Model is a Reaper and constitutes 2 parts; the scythe and body

Material Node Graphs:

Answer 1

As discussed in this issue, Blender's glTF importer/exporter works best with metal/rough PBR materials — not spec/gloss PBR materials. Because glTF's metal/rough workflow does include control of the specular parameter (extension: KHR_materials_specular), this is just as flexible and generally recommended when using glTF anyway.

Options —

1. Scale the model in a tool that fully supports spec/gloss, like Gestaltor, or the https://gltf.report/ script tab —

const scene = document.getRoot().listScenes()[0];

// Scales the direct children of the scene, ignoring any descendants.
// Overwrites any previous scale on these nodes.
for (const child of scene.listChildren()) {
    child.setScale([50, 50, 50]);
}

2. Convert from metal/rough to spec/gloss before editing in Blender, requires Node.js:

npm install --global @gltf-transform/cli
gltf-transform metalRough input.glb output.glb