If you've seen 3D relief carvings on CNC projects — a leaping fish emerging from a wooden plaque, or a mountain landscape with real depth — you've seen depth maps in action. Depth maps are the bridge between flat image files and three-dimensional carvings, and they're surprisingly easy to use once you understand the concept.
What Is a Depth Map?
A depth map is a grayscale image where the brightness of each pixel represents a height value. Think of it as a topographic map encoded as an image:
- White pixels = the highest point (material surface, untouched)
- Black pixels = the deepest point (fully carved away)
- Gray pixels = intermediate depths (lighter gray = shallower, darker gray = deeper)
Your CNC software reads this grayscale image and converts it into toolpaths that carve at varying depths, producing a three-dimensional relief from a flat piece of material.
Depth Maps vs. SVG Files
Standard SVG files are 2D vectors — they define flat shapes with uniform depth. You can pocket-carve an SVG at one depth or V-carve along its paths, but there's no built-in height variation within the design.
Depth maps add the third dimension. A depth map of an eagle doesn't just give you the eagle's outline — it gives you the raised beak, the recessed feather details, and the gentle curve of the wing. The result is a true 3D relief that looks and feels carved by hand.
| Feature | SVG File | Depth Map |
|---|---|---|
| Dimensions | 2D (flat shapes) | 3D (height data) |
| File format | .svg (vector) | .png, .bmp (grayscale image) |
| Carving style | Pocket, profile, V-carve | 3D relief carving |
| Detail level | Based on path complexity | Based on image resolution |
| Best for | Signs, cutouts, inlays | Wall art, plaques, decorative panels |
Creating Depth Maps with Craftgineer ReliefMaker
The easiest way to create depth maps is Craftgineer's ReliefMaker. Upload any image — a photo, illustration, or design — and ReliefMaker generates a 3D relief depth map ready for CNC carving. It converts flat images into grayscale height maps with proper depth information for relief carving, lithophanes, and laser engraving.
- Local mode (free): Process images using your browser — no upload needed
- Gemini mode (1 credit): AI-powered conversion for more complex images with better depth estimation
Instead of manually painting grayscale depth values in Photoshop or learning specialized 3D modeling software, ReliefMaker handles the conversion automatically. Upload your image, adjust the depth settings, and download a ready-to-carve depth map.
Software That Supports Depth Maps
VCarve Pro / Aspire
Vectric's software is the gold standard for depth map carving. Import a grayscale image, set the material thickness and maximum carving depth, and VCarve generates the 3D toolpaths automatically. Aspire adds the ability to edit and combine depth maps.
Carveco Maker / Carveco Maker Plus
Formerly called ArtCAM, Carveco specializes in relief carving. It imports depth maps as 3D reliefs and offers advanced tools for smoothing, combining, and editing the height data before generating toolpaths.
Fusion 360
Autodesk Fusion 360 can use depth maps as displacement maps on surfaces, then generate 3D toolpaths from the result. This takes more setup than dedicated relief-carving software but works within a full CAD/CAM workflow.
Carbide Create Pro
The Pro version of Carbide Create supports 3D modeling and can work with height fields. It's simpler than VCarve but handles basic 3D projects well for Shapeoko and Nomad users.
How to Use a Depth Map: Step by Step
- Import the depth map — Open your CAM software, create a new project with your stock dimensions, and import the grayscale image as a 3D component or relief.
- Set the dimensions — Scale the depth map to match your workpiece. Set the maximum depth (how deep the darkest areas will carve).
- Choose your bit — Ball-nose bits are standard for 3D relief carving. A 1/4" ball nose handles roughing; a 1/8" or smaller handles the finishing pass for fine detail.
- Generate roughing toolpath — A larger bit removes the bulk of the material quickly. Set a reasonable stepover (usually 40-50% of bit diameter) and appropriate feeds and speeds for your material.
- Generate finishing toolpath — A smaller bit makes the final pass at a finer stepover (10-15% of bit diameter) to smooth the surface and capture detail.
- Simulate — Preview the toolpaths to verify the result before cutting.
- Carve — Run the roughing pass first, then the finishing pass. Don't remove or move the workpiece between passes.
Recommended Bit Sizes for Depth Maps
| Carving Size | Roughing Bit | Finishing Bit | Est. Time |
|---|---|---|---|
| Small (6" x 6") | 1/4" flat or ball | 1/8" ball nose | 1-3 hours |
| Medium (12" x 12") | 1/4" ball nose | 1/8" ball nose | 3-8 hours |
| Large (24" x 24") | 1/2" ball nose | 1/4" ball nose | 8-20 hours |
Tips for Great 3D Carvings
- Use quality wood — Tight-grained woods like maple, cherry, and walnut show 3D detail beautifully. Avoid soft, open-grained woods that fuzz up during carving.
- Sand between passes if needed — For premium results, lightly sand after the roughing pass to remove any fuzz before the finish pass.
- Apply finish carefully — A clear coat, Danish oil, or stain enhances the depth and makes the 3D relief really pop
- Keep sharp bits — Dull bits tear instead of cut, which destroys fine 3D detail
- Don't rush the finishing pass — A finer stepover takes longer but produces dramatically smoother results
Explore 3D-Ready Designs
Ready to create your own depth maps? Try ReliefMaker to convert any image into a carving-ready depth map. Then browse our CNC design collections for SVG files ready to carve on your router — every file includes commercial licensing.
For more CNC fundamentals, read our CNC router SVG guide or explore V-carving techniques.
