Reality Composer Pro material texture not shown when using .generateText in visionOS RealityView

Question

I have created an app for visionOS and opened Packages/RealityKitContent/package file in Reality Composer Pro. I clicked + button in top right corner and added Material Library/Generic/Metal/ScratchedMetallicPaint material to the default sphere. I can see the metal texture in bottom right corner.

I then use the material in my code as following everytime user selects new material in a picker Picker. After picking material newValue has value of ScratchedMetallicPaint

 var dynamicMateriala = try await ShaderGraphMaterial(named: "/Root/\(newValue)",
                           from: "Scene.usda",
                           in: realityKitContentBundle)
                            
// setting UV scale parameter did not help 
 try! dynamicMateriala.setParameter(name: "UV_Scale", value:  .simd2Float(SIMD2<Float>(repeating: 20)))
viewModel.dynamicMaterial = dynamicMateriala

In RealityView update closure:

let font = UIFont(name: "Arial", size: 0.07)
let resource: MeshResource = .generateText(message, extrusionDepth: 0.01, font: font)

if viewModel.dynamicMaterial != nil {
        let fontEntity = ModelEntity(mesh: resource, materials: [viewModel.dynamicMaterial!])
 }

Problem: ViewModel is ObservableObject and passes material correctly. The problem is that only base color of the material is passed and texture is not passed from Reality Compose Pro.

I found an answer to similar problem: similar but not sure how to to the solution.

I tried the following based on that answer which says we need to assign material to entity in RealityComposerPro first, but not even the first print is logged.

 if let scene = try? await Entity(named: "Root", in: realityKitContentBundle){
                            
                            print("In Root")
                            if let box = scene.findEntity(named: "Cube") as? ModelEntity {
                                print("In Cube")
                                
                                let materials = box.model?.materials
                                print("In Materials \(materials)")
                              
                            }
                        }

Does anybody know what might be the problem?
Thanks!

Answer 1

Controlling parameters in MaterialX

The problem lies in the incorrect value of the UV_Scale parameter - the higher this value (it's 20 in your code), the finer the grain of the material, that is, the more difficult to distinguish its texture (be it car paint or leather). To see texture details, you should decrease the UV scale value (the default is 1.0) rather than increase it.

import SwiftUI
import RealityKit
import RealityKitContent

struct ContentView: View {
    var body: some View {
        RealityView { content in
            var matX = try! await ShaderGraphMaterial(named: "/Root/Leather", 
                                                      from: "Scene.usda",
                                                      in: realityKitContentBundle)
                                 
            try! matX.setParameter(name: "UV_Scale",
                                  value: .simd2Float(.init(x: 0.7, y: 0.7)))
            
            let text = ModelEntity(mesh: .generateText("MaterialX",
                         extrusionDepth: 0,
                                   font: .systemFont(ofSize: 0.5, weight: .black)))

            text.model?.materials = [matX]
            content.add(text)
        }
    }
}

For developers:

Read this post to find out how to create a controllable input node in RCP.