Flipped normals with Collada Exporter

Hi guys,
I have created a mesh in three.js with BufferGeometry. I have tried exporting it with the ColladaExporter and GLTFExporter I found in the three.js docs. It exports the model but some of the faces are flipped. Since I have to import this model again at a second point in time, in another three.js scene it is an issue because the imported model doesn’t show correctly, most faces are invisible. I calculate the vertex normals with mesh.geometry.computeVertexNormals() and I suppose they are correct since when rendering the mesh before exporting all faces show. What could be wrong?

Thanks in advance :smile:

cound you show the code case?