Kerbal 3D Exporter

A Kerbal Space Program 1 editor/flight plugin for exporting the currently loaded (or active) craft as a 3D model suitable for visualization and 3D printing.

Features

• Export the current craft directly from the VAB, SPH, or Flight
• Export to multiple formats:
• Binary STL
• Wavefront OBJ
• 3MF (3D Manufacturing Format)
• STEP / .stp (ISO 10303 AP214, faceted B-rep, for CAD rather than printing)
• Export any combination of formats in one run
• Adjustable export scale
• Model coordinates are always relative to the craft's root part (placed at 0, 0, 0), regardless of where the craft is positioned in the world
• Launch clamps excluded from export by default (with toggle to include)
• Collapsible engine list showing every engine with per-engine shroud/fairing toggle
• Bulk "All Shrouds On"/"All Shrouds Off" buttons
• Collapsible Renderer & Collider Diagnostics window listing every renderer and collider-only mesh
• Individual Export checkboxes for each mesh with live filtering and hover-to-highlight
• Colliders with no material excluded by default with one-click bulk toggle buttons
• Part variant support: only active/selected variant meshes exported
• Optional user-authored exclusion list (shroud-exclusions.txt) for shroud/fairing refinement
• Toolbar button (via ToolbarControl) for easy access
• Progress window showing each export stage with cancel support
• Instruction files generated alongside each model describing recommended post-processing
• Mesh and part diagnostics files for troubleshooting
• Coroutine-based state machine to keep the game responsive during export

Installation

Install the mod into your KSP installation:

GameData/
  Kerbal-3D-Exporter/
    Plugins/
      Kerbal-3D-Exporter.dll
    Icons/
      toolbar-icon.png
      toolbar-icon-24.png
  000_ToolbarControl/
    Plugins/
      ToolbarControl.dll
      ClickThroughBlocker.dll

Dependencies: - ToolbarControl is required for the toolbar button (download separately if not already installed) - (Optional) Install the included ModuleManager patch to add the exporter to command pods

Usage

1. Start Kerbal Space Program
2. Enter the VAB, SPH, or Flight
3. Load a craft (or use the currently active vessel in Flight)
4. Open the exporter window using either:
5. The toolbar button (top-right stock toolbar or Blizzy's Toolbar if installed), or
6. Right-click a command pod with the exporter module and select "Open Craft Exporter"
7. Configure the export options
8. Click Export

The exporter displays its progress while generating the model.

Export Options

Scale

Controls the size of the exported model.

• Default: 0.01
• Minimum: 0.001

The exporter converts KSP's internal meter units into millimeters before applying the user scale.

Examples:

Model Origin

The exported model's x/y/z coordinates are always relative to the craft's root part, which is placed at exactly (0, 0, 0).

Vertices come out of Unity in raw world-space coordinates (an arbitrary position in the VAB/SPH, or a position that can drift in Flight). The exporter normalizes all coordinates relative to the root part to ensure consistency.

Export Format

Choose any combination of:

• STL
• OBJ
• 3MF
• STEP (.stp)

Every selected format is written on the same export run.

About 3MF

3MF is the format most current slicers prefer. Unlike STL, it stores an indexed vertex list, so a shared vertex is written once instead of once per triangle, resulting in typically much smaller files.

3MF also records the unit (millimeters) inside the file, so the slicer doesn't have to guess the scale on import.

The .3mf written here is a plain OPC/ZIP package containing [Content_Types].xml, _rels/.rels, and 3D/3dmodel.model. It opens directly in Cura, PrusaSlicer, SuperSlicer, OrcaSlicer, Bambu Studio, and similar slicers.

Separate object + color per part:

When enabled (default), the 3MF contains one <object> per KSP part, tied together by an assembly object, instead of a single merged mesh. A slicer with support for multi-part models can see and manipulate each part separately.

Each part also gets its own color from a generated palette.

Important: These colors are SYNTHETIC and decorative. A KSP part is textured, not flat-colored, so there is no single honest "color of this part" to read out of the mesh. The colors are for visual distinction only.

Turning this sub-option off gives the older behavior: one merged, uncolored mesh.

Apart from per-part colors, the 3MF export is geometry only, the same as STL and OBJ. It carries no textures.

About STEP (.stp)

Read this before enabling STEP, as it is not simply "a better STL."

STEP is a boundary-representation CAD format. A KSP craft is a triangle mesh. The only faithful way across that gap is a faceted B-rep: every single triangle becomes its own flat face.

That is valid STEP and it opens in Fusion 360, SolidWorks, FreeCAD, Onshape, and similar tools. However, it is NOT a "real" CAD model. There are no smooth NURBS surfaces and no analytic cylinders—only explicit triangles.

STEP files are also large. A faceted B-rep needs roughly 17 STEP entities per triangle, so a 100,000-triangle craft produces something on the order of 1.7 million lines and 100+ MB. Opening such files in a CAD tool can be slow.

The model is written as a surface body (an open shell), not a closed solid. This is deliberate: a KSP craft is many overlapping part meshes and is not watertight, and a STEP solid that claims to be watertight but isn't will cause CAD tools to fail.

Most slicers cannot read STEP at all. Use STL or 3MF for printing. Use STEP when you want the craft inside a CAD package to build a display stand or mount around it.

Because slicers generally cannot open STEP, the "open viewer after export" option never hands it a .stp file. It opens the STL, 3MF, or OBJ instead.

STL Viewer / Slicer Executable

Optional path to the executable for an STL viewer or slicer, such as PrusaSlicer, Cura, MeshLab, or another viewer.

If "Open viewer after export completes" is enabled, the exporter opens the generated STL when STL export is selected. If STL was not exported, it opens the 3MF instead, and failing that, the OBJ.

If this field is blank and opening is enabled, the exporter attempts to open the model using the operating system's default file association.

Open Viewer After Export Completes

When checked, the exporter launches the configured viewer/slicer after a successful export.

The viewer is not launched if the export is cancelled or fails.

Show Engine Shrouds / Fairings by Default

Global master switch controlling whether engine shrouds/fairings are included in the exported model.

When disabled, supported shroud meshes are hidden before mesh collection and restored after export.

Per-engine toggles (in the Engine List) can only further disable a shroud when this is on; they cannot re-enable one when this global switch is off.

Exclude Launch Clamps

Checked by default. Excludes any part with a LaunchClamp module (stock launch clamps) from the export entirely, since they aren't part of the craft itself.

Uncheck to include launch clamps in the model.

Exclude Collider-Only Meshes

Colliders (physics-only meshes with no MeshRenderer—that's why they're invisible in-game) can be listed and toggled individually in the Renderer & Collider Diagnostics window.

Colliders with no material default to excluded automatically. Use "Disable colliders without a material" / "Re-enable all colliders" in that window to apply or undo this in bulk, or toggle them individually.

Engine List

• Collapsed by default; click "Show Engine List" to expand
• Lists every engine found on the craft with a checkbox for whether to include that engine's shroud/fairing
• "Refresh Engine List" rescans the current craft
• "All Shrouds On" / "All Shrouds Off" set every engine's checkbox at once

Renderer & Collider Diagnostics

• Collapsed by default; click "Show Renderer Diagnostics" to expand
• Lists every Renderer (MeshRenderer/SkinnedMeshRenderer) and every collider-only mesh found on the craft, one row per object
• Each row has an Export checkbox; unchecking excludes that specific object from the model, independent of any other setting
• Hovering a renderer row highlights it in the 3D view (colliders have nothing visible to highlight)
• A filter box narrows the list by part name, mesh name, path, material, or type
• "Refresh Renderers" rescans the current craft
• "Disable colliders without a material" / "Re-enable all colliders" bulk-toggle every collider row that has no material (in practice, every collider row)
• Export automatically refreshes this list before building the model, so these settings take effect even if this window was never opened

shroud-exclusions.txt (currently disabled)

Optional file at GameData/Kerbal-3D-Exporter/shroud-exclusions.txt.

Lets you specify additional PartName/Path/Material tokens to treat as shroud/fairing geometry. Applies only when shrouds/fairings are being hidden for that part or engine (i.e., it refines the shroud-hiding heuristics—it is not a general-purpose always-exclude list).

Use the generated *_mesh_diagnostics.txt file to find the exact tokens to add.

Output Location

All exported files are written to:

GameData/Kerbal-3D-Exporter/Models/

Example (from the VAB/SPH):

SaturnV_printable.stl
SaturnV_printable.obj
SaturnV_printable.3mf
SaturnV_printable.stp
SaturnV_printable_mesh_diagnostics.txt
SaturnV_printable_part_diagnostics.txt
SaturnV_printable_STL_instructions.txt
SaturnV_printable_OBJ_instructions.txt
SaturnV_printable_3MF_instructions.txt
SaturnV_printable_STEP_instructions.txt

In Flight, exported files use a _flight_current_printable suffix instead of _printable.

Export Process

The exporter performs the following steps:

1. Validate the current craft
2. Snapshot which meshes on parts with variants are already hidden
3. Prepare the output directory
4. Refresh the engine list
5. Apply the selected shroud visibility
6. Write part diagnostics
7. Collect meshes from all parts
8. Write mesh diagnostics
9. Remove invalid triangles
10. Remove duplicate triangles
11. Write STL (if selected)
12. Write STL instructions
13. Write OBJ (if selected)
14. Write OBJ instructions
15. Write 3MF (if selected)
16. Write 3MF instructions
17. Write STEP (if selected)
18. Write STEP instructions
19. Restore shroud visibility

Each stage is displayed in the exporter window.

Recommended Workflow for 3D Printing

The exported model is intended as a starting point for creating printable models.

Recommended workflow:

1. Export the craft
2. Import the STL or OBJ into Blender
3. Inspect for missing or unwanted geometry
4. Merge meshes using Boolean Union
5. Remove internal geometry
6. Repair non-manifold edges
7. Fill holes
8. Thicken fragile parts if necessary
9. Export the repaired model as STL
10. Slice with your preferred slicer

Limitations

The exporter works with meshes instantiated by Unity.

Some KSP-specific rendering features are not exported, including:

• Shaders
• Materials
• Textures (OBJ geometry only)
• Animations
• Particle systems
• Lights

Only the currently active/selected part variant's meshes are exported; other variants' meshes are excluded.

Some mods may generate geometry procedurally. Depending on implementation, the generated geometry may or may not appear in the export.

Because KSP crafts are assembled from many overlapping meshes, additional cleanup is typically required before producing a watertight mesh suitable for reliable 3D printing.

Troubleshooting

Export fails

Check the KSP log (KSP.log) for exception details.

Missing parts

Verify that all required mods are installed and the craft loads correctly in the editor.

A mesh is missing or unexpectedly included

1. Open the Renderer & Collider Diagnostics window
2. Use the filter box to find the mesh
3. Check whether its Export checkbox matches what you expect
4. Click "Refresh Renderers" to rescan the current live scene state
5. Check the *_mesh_diagnostics.txt file from your last export: every mesh is listed as either EXPORT or SKIP, with the specific reason it was skipped

Shrouds still appear, or a shroud is missing

Some engines implement shrouds differently than the stock ModuleJettison system. Try adding a token to shroud-exclusions.txt (see above), or toggle the specific renderer off in the Diagnostics window.

On engines that also have part variants, a shroud only detected by the name-heuristic fallback (not a real ModuleJettison shroud) will follow whatever the active variant already set, rather than being independently controlled by the global switch.

Large file sizes

Large crafts can contain millions of triangles. Consider reducing the model size or simplifying the mesh in Blender before slicing.

Future Improvements

Possible enhancements include:

• Shared-vertex OBJ output
• Vertex welding
• Mesh decimation
• Automatic watertight mesh generation
• Automatic Boolean union
• glTF export with materials
• ZIP package generation

License

GPLv3 (GNU General Public License version 3)

Disclaimer

This project is provided as-is without warranty. Use at your own risk.

Credits

AI applications used in the development of this project: - ChatGPT - Claude.ai - Github Copilot

Kerbal Space Program is © Squad / Private Division.