00mesh

OBJ

Wavefront OBJ

OBJ is a plain-text mesh format holding vertices, normals, texture coordinates and named groups, with materials in a side-car .mtl file. It is old, simple and read by essentially every 3D application.

Extension: .obj
MIME type: model/obj

01 Convert OBJ to something else

OBJ to STL Triangulates quads and n-gons. Recomputes every normal.
OBJ to 3MF Keeps your groups as separate printable objects.
OBJ to PLY Indexed geometry into the research-tool format.
OBJ to GLB Groups become nodes. One file, no side-cars.

02 Convert something else to OBJ

STL to OBJ Optionally merges the duplicate vertices STL creates.
3MF to OBJ Each 3MF object becomes a named OBJ group.
PLY to OBJ Text output that Blender, Maya and Cinema 4D all read.
GLB to OBJ Node transforms applied, meshes kept as named groups.

03 Related formats

STL
PLY
3MF
glTF
GLB

Opening a .obj file

If you landed here because something handed you a .obj file and nothing on your machine will open it, converting it to a format you already have a reader for is usually faster than installing new software. Every conversion above runs in this browser — the file is not uploaded, so it works on a locked-down work machine and on a file you are not allowed to send anywhere.