1. Start with the intended use

Explain what the object does, where it will be used and whether it must fit another part. Decorative pieces, scale models and enclosures call for different decisions. Identify visible surfaces, contact areas and dimensions that matter.

A model that looks right in a render may not be printable. It can contain overlapping surfaces, thin planes or details with no physical thickness.

2. Confirm units and dimensions

Set the units in your software and check the dimensions after importing the exported file again. Conventional STL does not carry an unambiguous unit declaration, so specify units in your brief. Give width, height and depth rather than describing the object as small.

For mating parts, include measurements of the other component. There is no universal assembly clearance: it depends on the process, material, orientation and manufacturer’s accuracy.

3. Inspect the mesh

Look for open edges, reversed normals, duplicate faces and self-intersections. A closed solid should clearly distinguish inside from outside. Automatic mesh repair can alter small holes and features, so inspect the repaired result.

Geometry tools such as STL Check in 3ds Max can help. Passing a mesh check does not prove that the part can be manufactured using your chosen process.

4. Agree walls, supports and part splits

Minimum wall thickness and feature size depend on technology and material. Ask the manufacturer for requirements for the specific process. Pay attention to long thin features, holes, overhangs and inaccessible surfaces.

Orientation affects surface quality and part behaviour. Large models may need splitting and a planned joining method. Powder and resin processes may require openings to remove unused material from enclosed spaces.

5. Export and review the result

Choose a mesh resolution that preserves curves without creating an unnecessarily large file. Reopen the export and check scale, completeness and orientation. If the manufacturer provides a layer preview, review it before production.

Include intended use, units, dimensions, quantity, preferred schedule and surface expectations with your enquiry. The production file needs the manufacturer’s assessment. Load-bearing or safety-related parts require a separate technical review.

Sources

Autodesk: exporting from 3ds Max for 3D printing; 3MF Consortium: format specifications.