Bench record / observed, repeated, explained
The right export depends on what the CAD recipient must do next. A compact watertight mesh suits a print check. A textured model needs appearance data. Reverse engineering often benefits from a dense reference mesh or section workflow. Selecting a familiar extension without naming the downstream task creates avoidable unit, texture, and revision errors.
This guide begins after the scan has passed the scale and feature checks. It leads to an export package that another workstation can open, verify, and trace back to raw evidence.
Write the handoff sentence
Complete this statement before opening the export dialog: âThe recipient will use the scan toâ¦â Possible endings include check assembly clearance, model replacement surfaces, fit curves to sections, print a visual replica, or preserve color reference.
Then list the deliverable the receiving application actually accepts. Autodesk Fusion can insert STL, OBJ, and 3MF as mesh bodies and asks for a unit type during insertion. Autodesk Inventor can import OBJ or STL geometry for measurement, sectioning, constraints, and reference work, while noting that imported mesh is not associated with its source file.
A mesh entering CAD remains sampled surface geometry. Automatic conversion to a clean parametric solid is a separate modeling operation. Promise editable design intent only after that reconstruction work has been completed and checked.
Keep a master before reducing anything
Save the scanner project with raw frames, alignment, and processing history in the applicationâs native format. Export a full-resolution master mesh from the verified branch. Record units, coordinate system, up axis, origin choice, face count, texture state, and processing revision in a plain-text manifest.
Make delivery meshes from copies of that master. Decimation, smoothing, hole filling, coordinate movement, and unit conversion should each produce a new named revision. A smaller file can always be recreated from a preserved master; lost detail cannot be recovered from the reduced copy.
Choose STL for simple triangle delivery
STL is widely supported and represents a surface as triangular facets. The Library of Congress format description notes that standard STL carries surface geometry without a standard facility for color or texture. Binary STL is generally more compact than ASCII STL.
Choose STL when the receiver needs a single-color triangle mesh for printing, basic reference, or a toolchain that explicitly requests it. Color records, multiple named parts, and workflows with material assignments need another tested format.
Treat units as handoff metadata. Autodesk documentation shows that STL and OBJ imports require the correct source-unit choice; a wrong selection can turn a millimeter value into the same numeric value in inches. State the unit in the manifest and file name, then test the exported span in the target application.
Choose OBJ when structure or appearance matters
Wavefront OBJ can describe polygonal geometry and organize elements into groups. Its traditional appearance workflow uses an associated MTL file, and textures may live in separate image files. The Library of Congress notes both its broad support and the interoperability problems that can occur with material and texture links.
Choose OBJ when the receiving workflow has been tested with OBJ groups, vertex information, or an MTL-plus-texture package. Deliver every dependent file in one folder with relative references intact. Opening the OBJ alone on the senderâs workstation leaves the receiving texture path untested.
For a geometry-only engineering reference, OBJ may still be useful if it preserves the grouping expected by the CAD or mesh tool. Record whether the exporter triangulated polygons and whether normals were written.
Consider 3MF after a receiver test
Some current CAD and manufacturing applications accept 3MF as a mesh exchange format. Fusion lists 3MF alongside OBJ and STL for mesh insertion and export. Support elsewhere varies by application version and workflow.
Choose 3MF when both sender and receiver have opened a representative test file and verified geometry, units, orientation, and any required attributes. A formatâs feature set has little value if the downstream application discards those features during import.
Keep PLY or point data when the next tool needs it
Scanner software may offer PLY, point clouds, or other native outputs. These can preserve vertex color or unmeshed evidence useful in inspection and specialized reverse-engineering tools. They are poor default choices when the named CAD application cannot import them directly.
The recipientâs confirmed import path should decide. A dual delivery is often sensible: a verified neutral mesh for immediate reference and a denser native or point-based file for specialist processing. Both files need the same coordinate and revision record.
Set resolution from the downstream feature
Every triangle has a cost in file size and interactive performance. Autodesk explains that exported mesh resolution affects how geometry is displayed and interpreted, and that mesh models are reference data rather than associative source models in Inventor.
Start with the verified master. Create a copy at a moderate reduction, import it into the target CAD tool, and repeat the critical feature measurements. Inspect holes, fine edges, fitted sections, and alignment datums. If the difference from the master exceeds the taskâs allowance, reduce less or preserve dense regions with an adaptive tool.
Report face count and the measured comparison. Words such as âhighâ and âmediumâ depend on software presets and versions; recorded counts and feature results travel with the file.
Decide how to handle holes and shells
A print workflow may require a closed, consistently oriented mesh with positive volume. A reverse-engineering workflow may prefer open observed surfaces over invented patches. Fusionâs mesh properties identify closure, orientation, positive volume, shell count, face count, and vertex count, which makes those properties useful in the delivery record.
Remove obvious background shells and fixtures on a copy. Keep small disconnected components that are genuine part geometry only if the receiver expects them. Record every filled region, especially functional bores, mounting faces, and mating edges.
Run the target toolâs mesh check after export. Exporters can change triangulation and normals, so a clean source project does not guarantee a clean delivered file.
Place the model in a useful coordinate system
Agree on origin and orientation. Assembly context may require an existing datum frame. A single-part reverse-engineering job may use a primary mounting plane, a secondary edge direction, and a hole center. Document the rule rather than merely writing âaligned.â
Preserve the untouched scanner-coordinate master. Apply the CAD transform to a delivery copy and record the transform or datum definition. On import, check up direction; Fusion exposes a control for exchanging vertical axes when inserting a mesh.
Perform a round-trip acceptance test
Close the source application. On another workstation or clean target document, import the exact delivery file using the manifestâs units. Check:
- overall scale against a verified span;
- origin and up direction;
- face and shell count where the target reports them;
- normals and visible inside-out regions;
- open boundaries or unintended repairs;
- critical hole and edge measurements;
- groups, materials, and texture paths when included.
Autodeskâs Insert Mesh workflow makes units and position explicit, while its mesh section tools allow lines, arcs, circles, ellipses, and splines to be fitted to captured sections for reverse engineering. Testing those actual downstream operations is stronger than confirming that a thumbnail appears.
Package the handoff
Use a folder name with part identifier and revision. Include the delivery mesh, checksum, manifest, verification report, processing note, and any MTL or texture dependencies. If policy permits, include a view-only image showing orientation and named datums. Local assets keep the package portable.
The manifest should state the source project, scanner and software version, export date, format, units, coordinate system, face count, mesh repairs, decimation setting, verified features, known gaps, and intended use. Add a clear limitation if the file is for reference rather than manufacturing inspection.
Archive the raw project, verified master, delivery package, and import-test result together. The recipient receives a usable file, while the shop retains enough evidence to reproduce or revise it without rescanning immediately.