If you want to import STL files in Vectric Aspire and get a clean, carveable relief every time — this guide covers everything. From the first click to the final toolpath, with the exact settings that work for wood carving.
No unnecessary theory. Just the steps that matter.
What Happens When You Import an STL File in Aspire
Before touching any settings, it helps to understand what Aspire actually does when you import an STL file.
Aspire reads the triangular mesh of the STL and converts it into a height map — a grayscale representation of depth. Every point on the surface gets a Z value. Aspire then treats this height map as a relief component that can be placed, scaled, and combined with other elements in your job.
This is why not all STL files work equally well in Aspire. A file designed for 3D printing has a fully enclosed mesh — top, bottom, and sides all sealed together. Aspire can handle this, but the result is often disappointing because the software has to guess which side is the “top.” A file designed specifically for CNC relief carving has a flat bottom and an open top surface — Aspire reads it cleanly and the result is exactly what you see in the preview.
The rule: always use STL files specifically designed for CNC relief carving, not files converted from 3D printing models.
Step 1 — Set Up Your Job Correctly First
Before importing anything, your job setup must match your material. This is the most common mistake beginners make — they import the STL first and then discover the proportions are wrong.
Go to File → New and set:
- Width and Height: the actual size of your workpiece in mm or inches
- Thickness: the actual thickness of your material — for beech or oak panels, typically 18–30 mm
- Z Zero Position: set to the top of the material for relief carving
- XY Datum: bottom left corner is the standard
Click OK. Your job is now ready to receive the STL.
Step 2 — Import the STL File
Go to Model → Import Component / 3D Model in the top menu. In older versions of Aspire this may appear as File → Import → Import Component.
A file browser opens. Navigate to your STL file and click Open.
Aspire will now show you the STL Import dialog. This is where most of the important decisions happen.
Step 3 — The Import Dialog — Every Setting Explained
Initial Orientation This tells Aspire which face of the STL is the “top” — the surface that will be carved. For a properly designed CNC relief file, the correct orientation is usually Back or Top depending on how the file was exported. If your preview shows the model upside down or flat, try switching between these options until the relief faces upward.
Scale to fit job size This automatically scales the model to fill your job dimensions. Useful as a starting point, but check the aspect ratio — if your job is 400×300 mm and the model is square, Aspire will stretch it. Better to uncheck this and set dimensions manually.
Scale to fit job size This automatically scales the model to fill your job dimensions. Useful as a starting point, but check the aspect ratio — if your job is 400×300 mm and the model is square, Aspire will stretch it. Better to uncheck this and set dimensions manually.
Height This controls the maximum depth of the relief — how deep the highest point will be carved. For a 20 mm thick panel, a relief height of 8–12 mm gives excellent results with strong shadow and depth. Going above 60% of your material thickness risks tearout on the back.
Zero Plane Position Set this to the bottom of the model. This ensures the flat base of the STL aligns with the surface of your material.
Click OK when you are happy with the preview.
Step 4 — Position and Resize the Component
After importing, the model appears as a component in your Component Tree on the right side of the screen. You can now:
- Move it by clicking and dragging in the 2D view
- Resize it using the handles or by typing exact dimensions in the toolbar
- Rotate it using the rotation handle at the top of the selection
For a single relief panel that fills the entire job, center the component and match it to your job dimensions. Use Edit → Align Selected Objects → Center in Job for precise centering.
Step 5 — Bake the Relief
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Once you are happy with the position and size, you need to bake the component into the job relief. This converts the component from an editable object into the final relief surface that toolpaths will be calculated from.
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Go to the Sculpting tab on the left panel and click Bake Components to Relief. Aspire will process the model and display the final relief in the 3D view.
At this point you should see a full 3D preview of your carving. If something looks wrong — the model is too flat, too deep, or distorted — go back to the Component Tree, double-click the component to re-edit it, and adjust the height or orientation settings.
Step 6 — Create the Toolpaths
Roughing toolpath — 3D Roughing
- Tool: 6 mm ball nose or flat end mill
- Stepover: 40–50% of tool diameter (2.4–3 mm)
- Stepover: 40–50% of tool diameter (2.4–3 mm)
Finishing toolpath — 3D Finishing
- Tool: 1.5–3 mm ball nose bit
- Stepover: 0.3–0.5 mm — this determines surface smoothness
- Strategy: Raster at 45° for the smoothest result on most models
For detailed models like animal portraits or baroque ornaments, a second finishing pass at 90° to the first (crossing the raster lines) eliminates any remaining ridges and produces an extremely smooth surface.
Common Problems and How to Fix Them
Problem: The model appears completely flat after import Cause: The STL file has its top surface facing downward. Fix: In the import dialog, change Initial Orientation from Top to Back, or try all four options until the preview shows the relief correctly.
Problem: Aspire shows “mesh errors” or the model looks broken Cause: The STL file has non-manifold geometry — open edges, duplicate faces, or inverted normals. This is common with files designed for 3D printing. Fix: Use a file specifically designed for CNC carving. If you must use the file, run it through Meshmixer (free) to repair the mesh before importing.
Problem: The relief looks correct in Aspire but carves too shallow on the machine Cause: The Z zero was set incorrectly, or the relief height in the import dialog was too low. Fix: Increase the Height value in the import dialog to 10–15 mm and re-bake, or check that your Z zero probe touched the top of the material, not the spoilboard.
Problem: Fine details disappear in the carving Cause: The finishing bit is too large for the detail level of the model, or stepover is too wide. Fix: Switch to a 1 mm ball nose bit for the finishing pass and reduce stepover to 0.2–0.3 mm. Machine time will increase but detail will be dramatically better.
Problem: The model is stretched or distorted Cause: XY Lock ratio was unchecked during import and the model was scaled non-uniformly. Fix: Delete the component, re-import the STL with Lock XY ratio checked, and re-scale proportionally.
Recommended STL File Settings for Common Materials
| Material | Relief Height | Roughing Bit | Finishing Bit | Finishing Stepover |
|---|---|---|---|---|
| Beech 20mm | 8–10 mm | 6 mm ball nose | 1.5–2 mm ball nose | 0.4 mm |
| Oak 25mm | 10–12 mm | 8 mm ball nose | 2 mm ball nose | 0.4 mm |
| Walnut 20mm | 8–10 mm | 6 mm ball nose | 1.5 mm ball nose | 0.3 mm |
| MDF 18mm | 6–8 mm | 6 mm flat end | 2 mm ball nose | 0.5 mm |
FAQ — Quick Answers
Can I use free STL files from Thingiverse in Aspire? You can try, but results are inconsistent. Most Thingiverse files are designed for 3D printing with closed geometry. They often import with orientation problems or appear flat. Files specifically designed for CNC relief carving — with a flat base and open top — always import cleanly and produce better results.
What is the difference between Aspire and VCarve Pro for STL import? Both support STL import through the same dialog. The key difference is that Aspire allows full 3D component editing and sculpting after import, while VCarve Pro imports STL files as fixed components without the ability to sculpt or edit them. For complex multi-layer reliefs, Aspire gives you more control.
How do I scale the model to a specific size after import? After importing, select the component and use the W (width) and H (height) fields in the toolbar at the top of the screen. Type your target dimensions and press Enter. Make sure the lock icon between W and H is closed to maintain proportions.
My machine has a small bed — can I scale the STL down? Yes. During import, uncheck Scale to fit job size and manually enter your desired dimensions. Aspire scales the relief height proportionally, so a smaller carving will automatically have a shallower relief. If the result looks too flat, manually increase the Height value in the import dialog.
Where to Find STL Files That Work in Aspire Every Time
Every model in our collection is designed specifically for CNC wood carving — tested in Vectric Aspire and VCarve Pro, with a flat base, correct relief depth, and clean mesh. Each file includes a commercial license so you can sell finished pieces.
👉 Browse all Animal STL Files — lion, owl, tiger, koala and more 👉 All CNC Router STL Models
For the official Vectric documentation on importing 3D models, visit Vectric’s support page.
Related: setting up toolpaths in Vectric and the guide to choosing an STL file.
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