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FBX Exporter not exporting UV4, 5, 6, 7

Discussion in 'Formats & External Tools Previews' started by olix4242, Apr 26, 2022.

  1. olix4242


    Jul 21, 2013
    FBX exporter currently doesn't export UV channels bigger than UV3.
    A fix is quite easy, I just had to change a code in exporter package.

    Code (CSharp):
    1.         /// <summary>
    2.         /// Unity has up to 4 uv sets per mesh. Export all the ones that exist.
    3.         /// </summary>
    4.         /// <param name="fbxMesh">Fbx mesh.</param>
    5.         /// <param name="mesh">Mesh.</param>
    6.         /// <param name="unmergedTriangles">Unmerged triangles.</param>
    7.         private static bool ExportUVs(FbxMesh fbxMesh, MeshInfo mesh, int[] unmergedTriangles)
    8.         {
    9.             Vector2[][] uvs = new Vector2[][] {
    10.                 mesh.UV,
    11.                 mesh.mesh.uv2,
    12.                 mesh.mesh.uv3,
    13.                 mesh.mesh.uv4,
    14.                 mesh.mesh.uv5,
    15.                 mesh.mesh.uv6,
    16.                 mesh.mesh.uv7
    17.             };
    If you look at a comments for a code, you will notice that it says that it only exports first 4 channels because Unity supports only 4 channels. Unity internally supports up to 8 channels, so a code in a package should be changed to reflect this.
    Here comes another problem: even if Unity internally supports more than 4 uv sets (when a mesh is generated procedurally) it's FBX importer can't import other than 4 UV channels. This is an extremely limiting factor in some cases.