Convert STL to OBJ — Free, In Your Browser

About This Converter

An STL file is a bag of triangles. Every facet is stored as three corner points plus the direction that facet faces, and that is the whole vocabulary: no colour, no texture coordinates, no material, no unit declaration, and no vertices shared between neighbouring triangles. OBJ is a plain-text format with a much wider one. It can hold vertex positions, texture coordinates, per-vertex normals, named objects and groups, and a reference to a separate material file. Nothing is lost going this direction, because there is nothing in an STL that OBJ cannot express. What you should not expect is anything gained. The OBJ that comes out carries positions and normals; it has no texture coordinates and no companion material file, because the STL never had them. If you were hoping colour would appear, it will not, and you assign that in your 3D software afterwards. One detail does carry over and catches people out. STL normals describe facets, not vertices, so the model keeps its faceted look in OBJ. A curved surface that was triangulated coarsely still reads as a low-poly gem after conversion; smooth or recompute the normals in your mesh editor if you want a soft surface. Expect the file to grow, often several times over. OBJ writes its numbers as text, and the triangles arrive unshared, so a vertex used by six triangles is written out six times. That is a fair trade when you are heading into an editor and a poor one if you were only trying to shrink a file. Neither format states its units. An STL exported in millimetres and one exported in inches are indistinguishable on disk, and OBJ does not fix that; the preview here also normalises the model so it fits the viewer, so treat your download as shape rather than as measured dimensions and set the size you want in whatever opens it. OBJ is the safer import for Blender, MeshLab, 3ds Max, Cinema 4D and most rendering tools, which is the usual reason to make this trip at all. Keep the original STL for slicers, which want STL. Scene Editor reads either. All of it happens in your browser: the file never leaves your machine, and there is no account to create.