How to Export STEP Files from Altium Designer: Complete Guide for ECAD-MCAD Collaboration

After years of handing off PCB designs to mechanical engineers who then discover fit issues inside enclosures, I’ve learned that STEP file export from Altium Designer isn’t just a nice-to-have—it’s essential for any product where the board needs to fit inside something. This guide covers everything from basic export procedures to advanced Output Job configurations, troubleshooting common problems, and understanding when STEP files make sense versus other collaboration methods.

What Is a STEP File and Why Export from Altium Designer?

STEP (Standard for the Exchange of Product model data) is an ISO-standardized 3D file format (ISO 10303-21) that provides a universal way to transfer CAD data between different software applications. When you export a STEP file from Altium Designer, you’re creating a 3D representation of your PCB assembly that mechanical engineers can import into their MCAD tools—SolidWorks, Creo, Inventor, Fusion 360, or any other CAD software that supports the format.

The critical function here is clearance checking. When your PCB design must fit inside an enclosure with exposed connectors, switches, displays, and controls, the mechanical designer needs accurate 3D data to verify everything fits before committing to tooling. STEP files provide this with high dimensional accuracy, making them the standard handoff format between ECAD and MCAD worlds.

What Gets Exported in an Altium STEP File

Element	Included	Notes
Board substrate	Yes	Full 3D shape including cutouts
Component 3D bodies	Yes	Both STEP models and extruded shapes
Pad holes	Optional	Configurable in export settings
Vias	Optional	Configurable in export settings
Copper traces	No	Not included in STEP export
Silkscreen	No	Not included in STEP export
Solder mask	No	Color only, not geometry

Understanding these limitations upfront prevents frustration. STEP exports focus on physical geometry for mechanical fit checking, not visual rendering of the complete board.

Enabling the STEP Exporter in Altium Designer

Before you can export STEP files, you need to ensure the STEP Exporter extension is enabled. This isn’t always activated by default during installation.

How to Enable STEP Export

1. Click the user button at the top right of Altium Designer
2. Select Extensions and Updates
3. Click the Installed tab
4. Click the Configure link under the Platform section
5. Locate STEP Exporter in the Importers/Exporters list
6. Check the box to enable it
7. Restart Altium Designer if prompted

If you don’t see the STEP export option in your File menu after following these steps, verify your Altium license includes this capability. Some legacy or limited licenses may not include 3D export features.

Step-by-Step Guide to Export STEP Files from Altium Designer

The basic export process is straightforward, but understanding each option ensures you get the right output for your mechanical team.

Method 1: Direct Export from PCB Editor

1. Open your PCB document in Altium Designer
2. Verify your design in 3D view (press 3 to switch to 3D mode)
3. Navigate to File → Export → STEP 3D
4. Choose your save location and filename
5. Configure the Export Options dialog (detailed below)
6. Click OK to generate the file

Method 2: Export via Output Job File

For production workflows where consistency matters, use an Output Job file:

1. In the Projects panel, right-click your project
2. Select Add New to Project → Output Job File
3. In the OutJob editor, click Add New Export Output
4. Choose Export STEP → [PCB Document]
5. Double-click the new entry to configure export settings
6. Assign an output container and generate

The Output Job method offers additional options not available in direct export, including selective hole export by category (mechanical, electrical, free pads).

Understanding STEP Export Options in Altium Designer

The Export Options dialog controls what gets included in your STEP file. Making the right choices here directly impacts file size, export speed, and usefulness to your mechanical team.

Components With 3D Bodies Options

Option	Description	When to Use
Export All	Includes every component	Complete assembly for fit checking
Export Selected	Only selected components	Partial exports, specific areas

Pro tip: If you select “Export Selected” but have nothing selected in the PCB editor, the export will include only the bare board with no components. This is useful when mechanical engineers need just the board outline for initial enclosure design.

Pad Holes Options

Option	Description	File Size Impact
Export All	Every hole in the board	Larger files, slower export
Export Selected	Only selected holes	Smaller files, faster export

Through Output Job files, you get additional granularity:

• Export Mechanical Component Pad Holes: Mounting holes and hardware
• Export Electrical Component Pad Holes: Through-hole component pins
• Export Free Pad Holes: Standalone vias and test points

3D Body Type Preferences

When components have both simple extruded bodies and STEP model bodies assigned:

Setting	Result	Best For
Prefer simple bodies	Uses extruded shapes	Smaller files, faster export
Prefer generic 3D models	Uses STEP models	Accurate component representation
Export both	Includes both types	Maximum compatibility

Export As Single Part Option

This setting significantly affects how your mechanical engineer works with the imported model:

• Disabled (default): Exports as assembly with selectable components
• Enabled: Exports as single solid part

Choose “Single Part” when you want to prevent mechanical engineers from accidentally moving components, or when your MCAD software has trouble with complex assemblies. Leave it disabled when they need to manipulate individual components.

Export Folded Board (Rigid-Flex Designs)

For rigid-flex PCBs, the Export Folded Board option lets you control the flex state:

1. Check Export Folded Board
2. Use the Rate slider to set fold percentage (0% flat to 100% fully folded)
3. The default matches your current Fold State setting in the PCB panel

This feature is essential for verifying rigid-flex boards fit correctly in their assembled configuration.

Coordinate System and Origin Considerations

STEP files exported from Altium Designer position the model relative to your PCB origin point. This matters because some MCAD applications handle the embedded location data differently.

Common Origin Issues

• Model appears off-screen: The MCAD software didn’t process location data correctly
• Model at unexpected position: Origin placement in Altium doesn’t match MCAD expectations
• Components floating separately: Usually indicates “Export as Single Part” setting mismatch

Best Practice for Origin Placement

Before exporting, verify your PCB origin location:

1. In PCB editor, go to Edit → Origin → Set
2. Place origin at a logical reference point (board corner is typical)
3. Document the origin location for your mechanical team

Consistent origin placement across revisions prevents the “where did my board go?” moments that plague ECAD-MCAD collaboration.

Troubleshooting Common STEP Export Problems

Over years of exporting STEP files from Altium, I’ve encountered these issues repeatedly. Here’s how to solve them.

Missing Components in Exported STEP

Symptom: Some or all components don’t appear in the STEP file.

Causes and Solutions:

Cause	Solution
“Export Selected” enabled with nothing selected	Select components or choose “Export All”
Components lack 3D body definitions	Add 3D bodies to footprints in library
3D bodies not properly linked	Verify 3D body file paths in component properties

Corrupted Geometry in MCAD Application

Symptom: Surfaces appear broken, fillets become toroids, or geometry displays incorrectly after import into Creo, SolidWorks, or other MCAD software.

Solutions:

For PTC Creo users, add this line to your config.pro file:

intf_in_surf_boundary_pref xyz

For SolidWorks users:

• Try importing as “Composite” rather than “Multi-body part”
• Use the “Stitch” option during import to convert surfaces to solids

File Size Too Large

Symptom: STEP files are hundreds of megabytes, slow to export and import.

Solutions:

1. Use “Export Selected” to include only necessary components
2. Choose “Prefer simple bodies” for components where detail doesn’t matter
3. Export without pad holes for initial fit checks
4. Consider exporting only connector and tall component areas

Components Not Moving with Board

Symptom: When repositioning the imported board in MCAD, components stay at original location.

Cause: Usually indicates the STEP file was imported as multi-body part instead of assembly, or components aren’t properly grouped.

Solution: Re-export without “Export as Single Part” and import as assembly in MCAD.

STEP Export vs. MCAD CoDesigner: When to Use Each

Altium offers two primary methods for ECAD-MCAD data exchange. Understanding when to use each saves time and frustration.

Traditional STEP Export

Advantage	Limitation
Universal compatibility	One-way data transfer
No additional licenses required	Manual re-export for changes
Works with any MCAD software	No incremental updates
Simple workflow	No design change tracking

Altium MCAD CoDesigner

Advantage	Limitation
Bi-directional synchronization	Requires supported MCAD software
Incremental design changes	Additional license cost
Native component linking	Setup complexity
Change proposal workflow	Learning curve

Use STEP Export when:

• Your MCAD software isn’t supported by CoDesigner
• You need a one-time handoff for manufacturing
• Working with external contractors who don’t have CoDesigner
• Simple designs with infrequent changes

Use MCAD CoDesigner when:

• Frequent design iterations require constant updates
• Complex enclosures with tight tolerances
• Teams need bi-directional change tracking
• Working with SolidWorks, Creo, Inventor, Fusion 360, or NX

Alternative Export Formats from Altium Designer

STEP isn’t the only 3D export option. Depending on your MCAD software, other formats might work better.

Format	Extension	Best For
STEP AP214	.step, .stp	Universal compatibility (default)
Parasolid	.x_t, .x_b	SolidWorks (smaller files)
VRML	.wrl	Visualization, non-CAD applications
IDF	.emn, .emp	Legacy MCAD exchange

Parasolid tip: For SolidWorks users, Parasolid export often produces smaller files with better import results than STEP. Access via File → Export → PARASOLID.

Useful Resources for Altium STEP Export

Official Altium Documentation

Resource	Description	Link
STEP Export-Import Support	Official documentation	altium.com/documentation (search “STEP”)
Export Options Dialog	Detailed option explanations	altium.com/documentation
MCAD CoDesigner	Bi-directional collaboration	altium.com/documentation/altium-codesigner

3D Component Model Sources

Source	Description
Altium Content Vault	Built-in component library with 3D models
SnapEDA	Free 3D models, Altium format support
Ultra Librarian	Component models from manufacturers
3D ContentCentral	SolidWorks-hosted model library
GrabCAD	Community-contributed CAD models

STEP File Viewers (Free)

Tool	Platform	Notes
FreeCAD	Windows, Mac, Linux	Full CAD capability, open source
eDrawings	Windows, Mac	Free viewer from SolidWorks
Autodesk Viewer	Web-based	No installation required
3D-Tool	Windows	Free viewer with measurement tools

Frequently Asked Questions

Can I export copper traces and silkscreen in the STEP file?

No. Altium Designer’s STEP export includes only 3D body geometry—the board substrate, component bodies, and holes. Copper traces, silkscreen, and solder mask are not included. If you need trace visualization for marketing renders, consider using the 3D PDF export or third-party rendering tools that can process Altium’s native files.

Why is my STEP file so large?

Large STEP files typically result from detailed component models, especially connectors with complex geometry. Solutions include using “Export Selected” for specific components, choosing “Prefer simple bodies” in export options, or excluding pad holes. For initial fit checks, a simplified export is usually sufficient.

How do I export individual component STEP models from my library?

To extract individual 3D models: Create a simple PCB with just that component placed, export the entire board as STEP, then import into an MCAD tool like Fusion 360 where you can select and extract individual component models. Alternatively, if the component uses an embedded STEP model, you can find it in the component’s 3D body properties and access the original file.

Why do some components appear as simple boxes instead of detailed models?

Components display as extruded boxes when they have only simple 3D body definitions rather than STEP model bodies attached. To improve accuracy, assign proper 3D models to your library footprints. You can download STEP models from manufacturer websites, SnapEDA, or Ultra Librarian and link them to your footprints.

Can mechanical changes made in MCAD software be imported back into Altium?

Traditional STEP export is one-way only—changes in MCAD don’t flow back to Altium. For bi-directional collaboration, use Altium MCAD CoDesigner with supported MCAD software, or the IDX (Incremental Design Exchange) format for manual change exchange. Both methods allow mechanical engineers to propose board outline or component placement changes that electrical engineers can accept or reject.

Best Practices for STEP Export Workflow

Establishing consistent practices prevents the common mistakes that derail ECAD-MCAD collaboration.

Before Exporting

• Verify all critical components have accurate 3D models assigned
• Check that your board outline is properly defined with all cutouts
• Confirm the PCB origin is at a logical, documented location
• Switch to 3D view (press 3) and visually inspect the assembly

Naming Conventions

Use meaningful filenames that include project name, revision, and date:

ProjectName_Rev1.2_20250116.step

This prevents confusion when multiple STEP file versions exist and makes it easier for mechanical engineers to track which file corresponds to which design revision.

Communication with Mechanical Team

When sending STEP files, include a brief summary noting any limitations, origin location, and which components were included or excluded. This documentation prevents assumptions and reduces troubleshooting time.

Verifying Your STEP Export

Before sending files to your mechanical team, verify the export quality:

1. Import back into Altium: Place a 3D Body object, set it to “Generic” type, and import your STEP file to visually verify content
2. Use a free viewer: Open in FreeCAD or eDrawings to check geometry independent of Altium
3. Check file size: Unexpectedly small files might indicate missing components
4. Verify component count: Compare exported components against your BOM

Conclusion

Exporting STEP files from Altium Designer bridges the gap between electrical and mechanical design domains. While the process is straightforward—File → Export → STEP 3D—understanding the export options, coordinate system implications, and troubleshooting techniques makes the difference between smooth collaboration and frustrating back-and-forth with your mechanical team.

For simple, one-time handoffs, direct STEP export works perfectly. For complex products with frequent design iterations, consider investing in MCAD CoDesigner for bi-directional synchronization. Either way, maintaining accurate 3D models in your component libraries and establishing clear origin conventions with your mechanical team will save countless hours of rework.

The few minutes spent configuring export settings correctly pays dividends when your PCB drops into the enclosure model and everything fits on the first try.