Below is a guide on how to import SCHURKEE 3D scans and general datasets into CAD environments and how to get started, working with scans as your design reference.    

 

 

Sourcing a high accuracy 3D scan can be difficult in itself. Scan datasets are typically niche as is, but this becomes even more difficult with older vehicle models due to the added rarity and lack of continued aftermarket support as they are often forgotten.

However, once you have managed to source one, be it for an RX-7 FC3S, Z20 Soarer or Daihatsu Copen L880K, the next question we get is always the same:

How do I actually work with this in a CAD environment?

This guide has been put together to walk through the essential workflow, from importing a 3D scan STL and using it as an accurate design reference for anything from reverse engineering through to producing your own custom aero and bodykit designs for your projects or company.

What Is an STL Scan File?

First things first - to be able to understand the fundamentals, we have to start at square one. An STL file represents a 3D shape using thousands, or millions, of tiny triangles which together form a mesh. In the case of 3D scanning, this mesh is created using the data captured from the physical object. However, STL files aren't exclusive to 3D scanning, they're more commonly used for 3D printing (which you may recognise the format from most) as well as exporting mesh geometry from other 3D software.

Unlike traditional CAD geometry, an STL contains only triangulated mesh geometry. STLs have no feature tree or parametric history and instead represent the shape entirely through the mesh itself, which is both good and bad. It is good as it provides a good record of the real-world captured geometry from the scanner, but bad as it cannot be edited as easily - unlike a native CAD body.

At SCHURKEE, our 3D scans are captured at sub-millimetre accuracy, depending on the scan - this gives us a reliable reference for panel gaps, curvature transitions and mounting geometry.

Software Compatibility

Most professional CAD and surfacing tools can import STL directly:

• Fusion 360 - Insert > Mesh, you can then use the workspace to inspect or convert (depending on your licence type). It is important to follow these steps rather than importing the mesh through the 'open' command as this will likely import the mesh with incorrect dimensions.
  
  
• Rhino 3D - Native STL import; use MeshToNURBS for surface conversion (this is best for smaller meshes).
  
  
• CATIA / SOLIDWORKS - Import as a graphics body or use ScanTo3D (SOLIDWORKS Premium) for surface fitting.
  
  
• Blender - Great for visualisation, mesh cleanup and concept development. For downstream parametric CAD, the geometry may need to be rebuilt or be converted using dedicated CAD/reverse-engineering software.
  
  
• Geomagic Design X - This is the gold standard for reverse engineering workflows, and is purpose-built for converting scans into CAD models.
  

Step-by-Step: Importing and Aligning the Scan

1. Import the STL. In Fusion 360: click Insert > Insert Mesh. In Rhino: follow File > Import. Accept the correct units (millimetres as standard for SCHURKEE files).
2. Check scale. Measure a well-known dimension, be it the door jamb width or wheel arch radius, and compare against published chassis specs to confirm the scan is true to scale.
3. Orient to a datum. Align the mesh to your world origin using three-point alignment or by snapping to a flat reference surface (sill, bonnet shut line). Consistent orientation saves hours downstream. (SCHURKEE scans are supplied pre-aligned)
4. Reduce if needed. 3D scans can be heavy. Use Reduce Mesh or Modify > Reduce depending on what software you are using to reduce the polygon count for performance, without losing surface fidelity in key areas. Note that reducing mesh can lose important detail.

Using the Scan as a Design Reference

The most common workflow is to use the scan as a foundation, a locked reference body, while you build new parametric geometry on top of it. You can then:

• Sketch onto scan surfaces to capture panel profiles.
• Use section cuts to extract cross-sections at any station line - invaluable for aero, splitter or diffuser design.
• Measure clearances between new geometry and the scan body to validate fitment before cutting physical material.

We strongly recommend you check out Making for Motorsport's tutorial on reverse-engineering, specifically for working with 3D scans, using Fusion360 which hobbyists can get a free licence.

Reverse Engineering from a 3D Scan with Fusion360... for FREE!

Our Preferred Workflow

At SCHURKEE, our personal favourite workflow is to process scan data, once aligned, through dedicated reverse-engineering software such as QUICKSURFACE or Geomagic Design X, as these packages allow usable surfaces and CAD geometry to be reconstructed directly from the scan.

Additionally, the resulting geometry can then be exported into your CAD software of choice, giving you a much clearer and stronger foundation for designing parts, whilst also retaining the original scan as a reference for checking fitment and surface accuracy.

Common Pitfalls

• Unit scale errors. As mentioned earlier, the STL format has no embedded unit data, a file modelled in inches may import as millimetres in most tools, which can potentially make the car 25× too small. Always verify with a known dimension immediately after importing.
  
  
• Watertight vs. open mesh. In many cases, 3D scans are typically open meshes (such as only the exterior of the car being scanned, leaving no back faces). This is to be expected - don't try to close them unless your workflow specifically requires it.
  
  
• Over-converting. Avoid converting the entire mesh to NURBS in one pass. Instead, try to work section by section for a cleaner and more controllable surface. 

Ready to get started?

Browse the SCHURKEE scan library for your platform:

• Mazda RX-7 FC3S 3D Scan
  
• Toyota Z20 Soarer 3D Scan
  
• Daihatsu Copen L880K 3D Scan
  
• SCHURKEE Scan Library
  

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3D Scan CAD Reverse Engineering SCHURKEE STL Tutorial

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