If you want to prepare a model in AutoCAD for 3D printing, this guide explains in plain English what the 3DPRINT command does, how to use it step by step, common reasons it may fail and how to fix them, alternative ways to export printable files, and practical tips to get reliable STL/mesh output. This is a beginner-friendly, SEO-optimized guide for AutoCAD users preparing files for 3D printing.
What is the 3DPRINT command?
The 3DPRINT command in AutoCAD is a tool that helps you prepare 3D models for additive manufacturing. It gathers selected objects, checks basic compatibility, and exports a mesh file (commonly .stl) or sends the model to a configured 3D printer or print service. Use this command when you want to go from an AutoCAD solid model to a file format accepted by slicers and printing services.
Key points:
- Purpose: Export or prepare a 3D model for 3D printing.
- Typical output: STL (stereolithography) file, the standard for most slicers.
- Where to run it: Type 3DPRINT in the command line or locate it in the Output / 3D ribbon/menus depending on your AutoCAD version.
When should you use 3DPRINT?
- To create an STL for slicing software (Cura, PrusaSlicer, Simplify3D, etc.).
- When you need a quick mesh export from AutoCAD solids.
- To preview how your geometry will be interpreted as a mesh before printing.
How to use 3DPRINT — Step by step
Follow these steps to export a printable file using the 3DPRINT command:
Prepare your model:
- Ensure your model is a closed solid (not just surfaces or 2D geometry).
- Combine parts that should be a single object using UNION or similar operations.
- Place the model at/near the origin (optional but helps avoid coordinate issues).
Set units and scale:
- Confirm drawing units (TYPE: UNITS) — printers commonly expect millimeters.
- If your model was designed in inches, convert or scale accordingly.
Clean the geometry:
- Remove duplicate or overlapping faces and unnecessary small features that can cause mesh errors.
- Use OVERKILL (where available) to clean duplicate geometry in 2D; for 3D keep geometry simple.
- Ensure walls have non-zero thickness where required.
Run the 3DPRINT command:
- Type 3DPRINT into the command line or select it from the ribbon.
- When prompted, select the objects you want to export and press Enter.
Configure export options (dialog or prompts):
- Choose file type (usually STL).
- Choose binary (smaller file) or ASCII format if offered.
- Set mesh resolution or quality (coarser = smaller file, finer = larger file). If available, choose higher resolution for curved surfaces.
- Verify units and confirm whether AutoCAD will convert units on export.
Preview and export:
- Use the preview to check orientation and mesh quality.
- Save the STL to a known location.
- Open the STL in a slicer or mesh viewer to verify geometry.
If needed, repair the exported mesh using third-party tools (see Alternatives & Repair section).
Tip: Always save a backup of your DWG before performing destructive operations like unions or exploding blocks.
Common options and shortcuts
- Shortcut: type 3DPRINT at the command line.
- Ribbon: look in Output or 3D Tools depending on your workspace.
- Export alternative: use EXPORT and choose STL as the file type if your AutoCAD version doesn’t show an explicit 3DPRINT dialog.
Why 3DPRINT sometimes doesn’t work (Common errors and fixes)
Here are the most frequent reasons export or printing preparation fails, with fixes:
Problem: Model is made of surfaces or meshes, not solids.
- Fix: Convert surfaces to solids (if possible) or create closed solids using operations like EXTRUDE, REVOLVE, or by combining regions. If conversion isn’t possible, export a mesh format and repair in mesh software.
Problem: Model is not watertight (gaps, open edges, non-manifold geometry).
- Fix: Inspect the model for gaps. Use Boolean operations (UNION, SUBTRACT, INTERSECT) appropriately to close seams. Export to a mesh and repair with Meshmixer or Netfabb.
Problem: Thin or zero-thickness walls that cannot be printed.
- Fix: Add thickness with PRESSPULL, EXTRUDE, or by adjusting the original CAD features.
Problem: Scale/Units mismatch — object too large or too small in slicer.
- Fix: Confirm and set UNITS in AutoCAD before export. In the slicer, check import scale and unit settings. Export using the desired unit (mm recommended).
Problem: Overlapping or duplicate geometry creating mesh errors.
- Fix: Clean model by removing duplicates; use explode for complex assemblies and re-unite parts carefully.
Problem: Export fails or produces an error dialog without clear info.
- Fix: Save DWG, restart AutoCAD, try exporting only a subset of the model to isolate problem geometry. Use object isolation to detect the offending part.
Problem: Normals flipped or inverted faces after export.
- Fix: Inspect in a mesh viewer. If faces are inverted, repair in Meshmixer/Fusion 360 or run a mesh repair tool to recalculate normals.
Problem: Model uses blocks or references (XREFs) and they are not included.
- Fix: Bind external references or explode blocks as needed before export so all geometry is included.
Alternative workflows and tools
If 3DPRINT is unavailable or insufficient, these alternative methods and tools work well:
- Use AutoCAD’s EXPORT command and select STL as the file type.
- Export to OBJ or other mesh formats if your slicer supports them.
- Use Autodesk Fusion 360, Meshmixer, or Netfabb for advanced mesh conversion and repair (closing holes, fixing non-manifold edges, simplifying mesh).
- For complex assemblies, export individual parts and assemble/repair in a mesh tool or CAD-for-manufacturing software.
- Use dedicated STL export plugins or third-party converters when AutoCAD’s built-in options don’t meet quality requirements.
Third-party repair/inspection tools:
- Meshmixer — free and good for repairing, hollowing and support prep.
- Netfabb (Autodesk) — robust repair and analysis.
- Blender — advanced mesh editing (steeper learning curve).
- Slicer preview tools (Cura, PrusaSlicer) for quick inspection before printing.
Practical tips for reliable 3D printing from AutoCAD
- Design or export in millimeters unless you have a strong reason not to.
- Keep geometry manifold and watertight — hollow shells must be intentionally designed and sealed.
- Reduce unnecessary small features that increase mesh complexity and print time.
- Use binary STL for smaller files unless ASCII is required.
- Preview the STL in your slicer before printing to catch orientation and support needs.
- When in doubt, export a high-resolution mesh, then simplify in mesh software.
- For assemblies, consider printing parts separately and designing clear joints/tolerances.
FAQ
How do I check if my AutoCAD model is a solid suitable for 3D printing?
Check object properties: solids report as 3D solids in the Properties palette. Surfaces or regions will be listed differently. Use 3D visual tools (3DORBIT) to visually inspect for visible gaps and open edges.
Can I export multiple parts as one STL or do I need separate files?
You can export multiple parts in a single STL, but ensure parts are properly positioned and boolean-unioned if you want them printed as a single object. If parts are separate and intended to be assembled later, export them as separate STLs.
What is the best file format for 3D printing from AutoCAD?
STL is the most widely accepted format for 3D printing. OBJ may be useful when you need color or more mesh features, but most slicers accept STL.
My STL looks faceted with visible edges — how can I improve surface smoothness?
Increase mesh resolution on export or use a finer tessellation setting. If your version of AutoCAD allows adjusting mesh quality during export, choose a higher quality. You can also smooth in Meshmixer or by refining the CAD model.
Do I need to repair my mesh after export?
Often yes: AutoCAD exports can still contain small errors. Use Meshmixer or Netfabb to automatically repair holes, flip normals, and remove non-manifold edges before slicing.
Why does my slicer import the model at the wrong scale?
This is almost always a units mismatch. Confirm AutoCAD export units and slicer import units. Export using the unit the slicer expects (usually mm).
Can 2D drawings be printed on a 3D printer using 3DPRINT?
No — 2D drawings must be converted into 3D geometry (for example, EXTRUDE a 2D profile into a solid) before they are printable.
My model has thin walls and breaks during printing — how do I fix that?
Increase wall thickness in your CAD model to meet the minimum thickness requirements of your printer and material (often 0.8–1.2 mm or more depending on the machine). Use the slicer to inspect and measure thin areas.