Preparing a High-Contrast Height Map for STL
Turn grayscale artwork into predictable relief geometry. Learn contrast control, smoothing, and how to avoid banding and micro-noise before converting to STL.
Prerequisites
- A grayscale height map PNG (preferably 16-bit)
- An editor that supports 16-bit (Krita, Photoshop, or Affinity Photo)
- Omnvert converter
- A slicer (for relief preview)
Step-by-step
- 1
Start from 16-bit if you can
A higher bit-depth height map reduces banding. If you must use 8-bit, keep gradients smooth and avoid aggressive contrast jumps.
- 2
Normalize to clean grayscale
Convert to a single-channel grayscale image. Remove color noise and keep the background uniform. If the source has JPEG blocks, switch to PNG early to avoid amplifying artifacts.
- 3
Clean noise and compressional artifacts
Run light denoise or a tiny Gaussian blur. The goal is to remove speckles that would become spikes in the relief mesh.
- 4
Control contrast without clipping
Use levels/curves to set the dynamic range, but avoid crushing blacks/whites into flat plateaus unless that’s intentional. Clipping produces terraces and visible banding in the printed relief.
- 5
Convert to STL and validate relief
Upload the PNG to the PNG / SVG → STL converter, then inspect the surface in your slicer preview. If you see stepping/banding, reduce contrast or increase source bit-depth.
- 6
Sanity-check thickness and scale
Relief prints still need a base and a print-safe thickness. Verify X/Y/Z in the slicer and use Scaling & thickness as a reference for mm sizing.
Avoiding banding
- Prefer smooth gradients over posterized ramps.
- If you need strong contrast, apply it after denoise/smoothing — not before.
Recommended editor workflow
- Convert to grayscale, then denoise lightly.
- Use levels/curves to set dynamic range without clipping.
- Export as PNG (prefer 16-bit), keep it lossless.
- Convert to STL and validate the relief in slicer preview.
Relief printing tips
For shallow reliefs, use smaller layer heights (0.12–0.16 mm) to reduce stepping. For deeper reliefs, consider variable layer height if your slicer supports it.