Image to STL Converter

Convert grayscale images to 3D STL heightmap models for 3D printing.

Tested tool guide Tested browser tools Checked August 16, 2026

What Image to STL Converter does and how it behaves

Image to STL Converter turns tonal variation in a grayscale picture into a three-dimensional relief and packages that geometry as an STL model. Each image position contributes a relative height, so smooth gradients make slopes and abrupt black-to-white edges make sharp steps. The result is a heightmap surface, not a reconstruction of the photographed object's true depth. The most common surprise comes later: STL coordinates do not declare a unit, so a model intended as millimeters can import at the wrong physical size unless the receiving slicer or CAD application is given the intended scale.

How the result is produced

Tones become elevations

Image tone supplies the vertical information. Dark, midtone, and light samples are assigned positions across the available height span, and neighboring positions are joined into triangular faces. Blur therefore becomes gentle relief, banding becomes terraces, and isolated noise can become small peaks or pits. The source image's width-to-height ratio determines the relief footprint unless the model is deliberately rescaled.

STL contains geometry

Standard STL represents the resulting shape as a collection of oriented triangles. It carries no grayscale raster, texture, print material, layer height, or declared measurement unit. The exported file therefore describes geometry rather than printer instructions. Before slicing, confirm the imported dimensions and examine the base, side walls, and edges as a closed solid; visible relief alone does not establish printability.

Good uses

Convert a grayscale elevation image into a terrain-style relief, then scale and slice it as a physical topographic tile.
Turn high-contrast lettering, a logo, or line artwork into raised or recessed geometry for a plaque, stamp, or embossing master.
Create a shallow photo relief or lithophane-style panel after adjusting the source image so its tonal transitions produce the intended height changes.

Limits and checks

Brightness is treated as height information, not interpreted as lighting. Shadows, highlights, paint colors, and background gradients can all create geometry that was never part of the pictured object's shape.
Confirm which end of the grayscale range becomes higher. Reversing the tones changes raised regions into recessed regions and can produce the opposite of the intended plaque, mold, or terrain.
Image noise, compression artifacts, and tonal banding can appear as surface texture or terraces. Very fine relief may also disappear during slicing or printing, depending on the final scale and printer resolution.

Common questions

Does this recover the real depth of an object from a photograph?

No. A heightmap assigns elevation from tone, so a dark patch caused by paint or shadow is treated as height information just like a genuinely distant region. For believable shape, begin with an actual depth map or a deliberately drawn heightmap. An ordinary photograph can produce an interesting relief, but it is not metrically faithful to the pictured scene.

Is the exported STL ready to print at an exact size?

Not necessarily. STL supplies geometry but no unit declaration or slicer settings. After import, verify width, depth, total height, orientation, and whether the mesh is a closed solid. Then choose layer height, perimeters, infill, supports, and material in the slicer. If the receiving application assumes different units, correct the scale before generating printer instructions.

References and verification

The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.