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.3dm

Rhino 3D Model

CAD & 3D

3DM is Rhino’s model format for curves, NURBS surfaces, meshes and annotations. Compatibility depends on saved version and features; check units, tolerance, layers and dimensions even when the model renders.

Main use
Model masters containing curves, surfaces and meshes
Data type
Binary data
All sections, questions and sources

Content reviewed： · Editor：Kai

Opening steps

Choose your environment or purpose to see its steps.

Rhinoceros / compatible 3DM viewer

Preserve the original and inspect a working copy in a compatible application.

  1. Open a copy in compatible Rhino and review version notices.
  2. Inspect layers, units, a known dimension and object types.
  3. Review missing-font/invalid-object notices and save separately.
Inspect the received file and its requirements

Establish dependencies and settings before proceeding.

  1. Identify producer release, plug-ins and advanced features.
  2. Ask whether the recipient needs editable surfaces or only a mesh.
  3. Record model units and absolute tolerance.

Menu labels and support vary by app, OS and version. Preserve the original before making changes.

Troubleshooting by symptom

  • Older app rejects it: ask about saving to the target version.
  • Dimension text differs: inspect fonts and annotation settings.
  • Surfaces become mesh: inspect exchange format/settings.
  • History does not replay: inspect version/feature compatibility.

3DM → STEP / IGES / STL

  1. Choose STEP/IGES for suitable surface exchange or STL for mesh tasks, setting units and export options.
  2. Compare units, representative dimensions, surface joins and required annotations/layers.

STL tessellates surfaces; intermediate formats may lose history, annotations and plug-in data.

Surfaces and meshes are different editing objects

Identical appearance does not make NURBS surfaces and triangle meshes equivalent for editing. Agree on the required geometry type before a recipient attempts dimensional or surface changes.

Source for these steps：McNeel · Rhino (.3dm) Import/Export / McNeel · Index of import/export file types

Worked example: checks before handoff

Example: retain the 3DM master, export STEP for fabrication, then reopen it to check a known dimension and closed-solid status.

Source for these steps：McNeel · Rhino (.3dm) Import/Export / McNeel · Index of import/export file types

Related-format differences

Related-format differences
Format / methodPurpose and preserved information
.3dmModel masters containing curves, surfaces and meshes
STL / STEPSTL is mesh and STEP is CAD exchange, not the full 3DM master.
3DM → STEP / IGES / STLSTL tessellates surfaces; intermediate formats may lose history, annotations and plug-in data.

Handling and security

Review design confidentiality and the source of plug-ins and referenced assets.

Questions and answers

Does a viewer imply editing support?

Viewing and editing support differ; check required features and file version.

Does saving down retain everything?

Features/history absent from the target version may not be retained equivalently.

Can a mesh fully restore the original surfaces?

It need not reconstruct the same NURBS structure; obtain the surface master when needed.

Format facts: name, steward and MIME type
Formal name
Rhino 3D Model
Steward / specification
McNeel
MIME type
Consult the producer or delivery system. The extension alone does not establish a MIME type.

Primary and official sources