Qt Quick3D: Unable to Load STL/STEP/GLB Models in QML (Works Only with .mesh from Balsam)

SabarishR

Description:

I’m working on a Qt Quick3D application and facing issues loading 3D model files in QML.

Project Setup

Qt version: 6.8
Modules used: Quick, Quick3D, QuickEffects, Network, WebSockets, Charts
CMake-based project

I’ve included my CMake configuration below:

cmake_minimum_required(VERSION 3.16)
project(appsampleUI VERSION 0.1 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Qt6 REQUIRED COMPONENTS Quick Quick3D QuickEffects Network WebSockets Charts)
qt_standard_project_setup(REQUIRES 6.8)

qt_add_executable(appsampleUI main.cpp)

qt_add_qml_module(appsampleUI
    URI sampleUI
    VERSION 1.0

    QML_FILES
        Main.qml
       .........etc

    SOURCES
        SharedData.h
         .........etc

    RESOURCES
        .........etc
)

qt_add_resources(appsampleUI "assets"
    FILES
        meshes/bg.png
        meshes/logo.png
        meshes/link0.mesh
        meshes/link1.mesh
        meshes/link2.mesh
        meshes/link3.mesh
        meshes/link4.mesh
        meshes/link5.mesh
        meshes/m0.mesh
        meshes/m1.mesh
        meshes/m2.mesh
)

target_link_libraries(appsampleUI PRIVATE
    Qt6::Quick
    Qt6::Quick3D
    Qt6::QuickEffects
    Qt6::Network
    Qt6::WebSockets
    Qt6::Charts
)

Issue

When I use .mesh files generated using Qt Balsam, the models load correctly in QML.
However, when I try to load other formats like:
- .stl
- .step
- .glb

I get errors indicating that the files cannot be found or are not loaded.

Questions

Does Qt Quick3D support loading .stl, .step, or .glb files directly in QML?
If not, what is the recommended workflow for using these formats?
Is conversion to .mesh using Balsam mandatory for all 3D assets?
Could this issue be related to how resources are added in CMake (e.g., qt_add_resources)?

Additional Notes

Resource paths are referenced using the :/assets/ prefix.
.mesh files work fine from the same resource location.
Only non-mesh formats fail to load.

Any guidance or best practices for handling 3D model formats in Qt Quick3D would be greatly appreciated.

Thanks in advance!