OBJ-to-IGES Mesh -> BezierPatch / B-SplineSurface / NURBS-Surface convert.( IGES file ) Mesh -> IGES(BezierPatch/B-Spline/NURBS)-surface control point data file. The control point can be converted to IGES with "igescnv_write.exe" of https://github.com/Sanaxen/IGES-STEP-to-OBJ .