How to I prepare models for Canvas3D view?

[Aras]

I am trying to learn how to display and interact with 3D models in qt. One way I am trying is using the Canvas3D. I opened the canvas3d/interaction example and tried replacing barrel.json file with my own file. I am using blender and the threejs plugin to generate the json file. Right now I am using the default blender monkey mesh and converting it to json. I have not changed the code for the sample app at all -- just replaced the barrel.json with my generated monkey mesh. Instead of an interactive 3D monkey head, I get the following error:

Desktop_Qt_5_7_0_GCC_64bit-Debug/interaction...
QML debugging is enabled. Only use this in a safe environment.
qrc:/interaction.js:298: TypeError: Cannot read property 'vertices' of undefined

This error is happening because the call to parseJSON3DModel is failing and returning undefined. I add a console.log to the function below to verify that:

function handleLoadedModel(jsonObj) {
    log("*******************************************************************************************");
    log("handleLoadedModel ENTER...")
    var modelData = parseJSON3DModel(jsonObj, "");

    console.log("model is " + modelData);

    log("    "+theModel.verticesVBO);
    gl.bindBuffer(gl.ARRAY_BUFFER, theModel.verticesVBO);
    gl.bufferData(gl.ARRAY_BUFFER,
                  new Float32Array(modelData.vertices),
                  gl.STATIC_DRAW);

So my question is: why is the call to parseJSON3DModel failing on 3D json models? I have tried this with a few different meshes now. How can I create a mesh or modify the Canvas3D code so that I can display 3D content?

[upenya]

Try to triangulate faces of your mesh (select your shape, switch to Edit Mode and press Ctrl+T ).