Convert 3DP to OBJ

A modeling or fabrication tool may require OBJ when it cannot open a file from the application that created a 3D project. Conversion depends on the specific .3dp variant: the extension alone does not identify a mesh format.

What the 3DP format is

.3dp is used by different applications and is not one universal 3D standard. One known use is Autodesk 123D Catch project files, which can contain photo-reconstruction project data as well as model data. Identify the program that created the file before selecting a converter; a project container may not be directly readable as a mesh.

What the OBJ format is

OBJ is a widely supported text-based format for polygon meshes. It stores vertex positions and faces, and can include normals and texture coordinates. Materials and image textures are usually supplied separately in an .mtl file and image files. OBJ transfers static geometry, not the source project’s photos, reconstruction settings, animation, or application-specific scene data.

How to convert a 3DP file to OBJ

1. Find the application that created the file and open it there. Use its mesh export command to choose OBJ, if available. For a 123D Catch project, this requires a compatible installation of 123D Catch; the software has been discontinued, so the project may no longer be accessible through the original service.
2. If the source application cannot export OBJ but can export a mesh format Blender supports, export that intermediate file first. In Blender, use File → Import to load the mesh, then File → Export → Wavefront (.obj) to write the OBJ. Blender does not natively open arbitrary .3dp project files.
3. Keep any exported .mtl and texture images with the OBJ, preferably in the same folder. Open the result in the destination application and check that the mesh and materials appear correctly.

Do not change the filename extension to .obj; renaming does not convert the file. Use an online converter only if it explicitly supports the exact 3DP variant and its creator, since a generic converter may reject a project file or discard its project data.

Quality and compatibility

OBJ export preserves mesh data only to the extent supported by the source application. Check scale, orientation, face normals, UV coordinates, and texture paths after export; OBJ does not provide a consistent units declaration. For 3D printing, inspect the mesh for holes and non-manifold geometry in a repair tool or slicer.