Create a depth map for CNC that survives the move into CAM

A depth map for CNC states intended height across an area. Turning that into motion requires a cutter with a real radius, a machine with real acceleration, and stock that behaves. A field with a near-vertical step is geometrically valid and machinable only if the tool can reach it, which is why smooth, bounded transitions are usually worth more than dramatic contrast.

The practical consequence is that the depth map should be judged on slope and reachability, not only on how recognisable the subject is. Steep walls, thin ridges, and deep narrow valleys are the features that break a job after the design has already been approved.

A ball-nose cutter leaves a scalloped surface whose depth depends on stepover and diameter; a V-bit resolves points but flattens everything else; a small flat end mill needs clearance that a facial relief rarely has. Those constraints set how much relief the piece can carry before detail becomes unreachable or fragile.

Review the beam-or-tool comparison and the slope report before approving. They are cheap checks against real tool dimensions, and they answer the question a rendering cannot: whether the shape you designed is one this cutter can produce.

Maximum relief depth has to fit inside the stock after surfacing, and thin borders have to survive workholding. Neither is visible in an image, and both are common causes of a ruined blank on an otherwise correct file.

Run the project in the CAM package's simulation with real stock and the actual tool before cutting. Then check origin, units, and post-processor. The exported PNG or STL is prepared geometry: it carries no speeds, feeds, or machine safety, and it is never G-code.