Convert 3DP to STL

A slicer, CAD application, or 3D printer workflow may require an STL mesh when it cannot open the original .3dp file. Converting the file also creates a more portable mesh for inspection, editing, sharing, or archival storage.

What the 3DP format is

In 3D modeling, .3dp is an ambiguous extension used by particular 3D-printing, modeling, scanning, or printer-workflow applications. It is not one universally standardized mesh format, so the data structure depends on the software that created it.

A 3DP file may contain polygon geometry, object placement, build information, printer settings, or project references. Some variants contain an exportable mesh; others are project or job containers that cannot be converted independently. Identify the creating application before choosing a converter. An application’s native File → Export or File → Save As command is usually the most reliable method.

Do not confuse a 3DP project or print file with .stp or .step, which are standardized CAD-exchange formats.

What the STL format is

STL represents a surface as triangular facets. Its broad support in slicers, mesh-repair utilities, CAD importers, and 3D-printing services makes it a practical interchange format when the destination does not support the source file.

Binary STL is normally much smaller than ASCII STL and is the appropriate choice for most exports. STL stores tessellated surface geometry and facet orientation, but it does not standardize units, colors, textures, materials, object names, animation, printer settings, or exact CAD solids. Nonstandard STL color extensions exist, but they are not portable between applications.

How to convert a 3DP file to STL

Export from the creating application

1. Open the file in the application that created it and confirm that the model itself is present, rather than only a project or printer job.
2. Use File → Export or File → Save As, select STL, and choose binary output when available.
3. Set the export units and mesh resolution. Use chord-height, angular-deviation, or equivalent tolerances that preserve curved surfaces without producing an unnecessarily large mesh.
4. Open the exported STL in a slicer or mesh utility, verify a known dimension, and repair the mesh before generating a toolpath.

The native exporter is preferable because it can interpret application-specific 3DP data and often provides better control over scale and tessellation. If the program cannot export STL directly, export an intermediate mesh format such as OBJ or PLY if supported, then convert that mesh to STL.

Convert with 3D Object Converter

3D Object Converter is a Windows desktop utility that supports many specialized 3D formats and common mesh outputs, including STL. Support for a particular 3DP variant can differ by version, so verify that the installed edition recognizes the file before relying on it.

1. Open 3D Object Converter and choose File → Open.
2. Select the .3dp file and check the preview for the required model geometry.
3. If the program shows only project data, references, or an empty scene, open the file in its source application instead.
4. Choose File → Save As, select STL, and choose binary output.
5. Set scale or units if the program exposes those controls, save the file, and verify its dimensions in a slicer.

Use an online converter

Online services such as AnyConv may convert a 3DP variant to STL when that variant is included in their current supported-format list. Check the list first, upload the file, select STL, start the conversion, and download the result. Online services cannot interpret unsupported project containers, and uploading proprietary designs, personal scan data, or other confidential files may violate security requirements.

Quality and compatibility limits

STL has no dependable standard unit declaration, so a conversion can appear 10, 25.4, or 1000 times too large or too small when source and destination applications assume different units. Measure a known feature in the slicer or mesh editor and apply the correct scale before printing.

A coarse source mesh remains faceted after conversion; increasing the export resolution cannot restore detail that is absent from the source. Excessive tessellation increases file size and processing time without adding printable detail. Inspect curved surfaces and choose a tolerance appropriate to the model’s dimensions and printer accuracy.

The resulting STL can contain holes, duplicated facets, inverted normals, self-intersections, or non-manifold edges. Run the slicer’s mesh check or repair the file in MeshLab, Netfabb, or 3D Builder before slicing. Geometry, colors, textures, separate-object metadata, and printer-specific settings stored in the original 3DP file are discarded unless the source application exports them separately.