Mysterious .OBJ file doesn’t appear in my scene (But others do)

Questions
9

Okay I succeed to get the part of code which is problematic …

I have a code to Smooth the geometry which is the following :

export function setSmoothGeometry(geometry,tolerance=1 ) {
    // https://discourse.threejs.org/t/solved-how-can-we-smooth-model-loaded-with-objloader-i-e-not-flat-shading/5531/7
    
    const merged = mergeVertices(geometry,tolerance ); // this is a mystery
    // tempGeometry.mergeVertices();
    merged.computeVertexNormals();
    return merged
}

from this old topic : [SOLVED] How can we smooth model loaded with OBJLoader (i.e. not flat shading)? - #7 by Mugen87

I do not totally get what’s the tolerance for … But with the NOTOKAY file if I let the tolerance to 1 the geometry disappears