Lithophane Shapes Workbench three.js r128 · flat, curved, lampshade

A lithophane maker for more than flat panels. The same brightness-to-thickness relief, wrapped onto an arc or tiled around a tapered lampshade, with the smooth face towards the light.

Starting…

Image Choose image… Sample image. Choose a file, drop one on the preview, or paste.

View

Relief Backlit

Shape

Flat Curved Lampshade

Width100 mm Overall width including the border, measured along the curve. Height follows the image.

Thinnest0.6 mm Thickness at white. Keep it at two or three printed layers.

Thickest3.0 mm Thickness at black. Past about 3 mm most white filament is already opaque.

Sample pitch0.20 mm Grid spacing. Below half the nozzle width only the file gets bigger.

Gamma1.00 Below 1 thins the midtones, above 1 thickens them.

Smoothingoff Box blur radius in samples. Takes the edge off noise and JPEG blocks.

Border2.0 mm Solid frame at full thickness. At 0 the image runs to the edge.

Options NegativeBright prints thick, for viewing by reflected light MirrorFlips left to right, for viewing from the flat side

Things to try

Lampshade. Three copies on a 100 to 70 mm taper, then switch to backlit and look down into it.
Taper. Swap the two diameters. The image stretches at the wide end and squeezes at the narrow one; the height shrinks as the wall leans.
Copies. Each copy takes an equal share of the circumference, so one copy of a landscape photo makes a tall tube and six make a short band.
Curved. Take the arc from 20° to 340°. The width stays put and the radius tightens around it.

Drag to rotate, scroll or pinch to zoom, double-click to reset. Keys: B backlit, D download, 0 reset view, F full screen.

Pipeline

The image becomes a thickness grid exactly as in the Lithophane Workbench. For a lampshade the grid is repeated once per copy and joined end to end.
Grid columns become angles around a vertical axis and rows become heights. Each sample is pushed outwards from a smooth inner cone by its thickness.
The inner face is one long quad per column, since a cone is straight along its length. Flat rings close the top and bottom; an open arc also gets two end walls.
The STL stands upright, axis on Z, bottom rim on Z = 0, ready to print as it will hang.

Taper

w = π (r_bottom + r_top) / copies
L = w · (image height / image width) + 2 · border
h = √(L² − (r_top − r_bottom)²)
r_outer = r_inner + t · L / h

Each copy is w wide at mid-height, which sets the slant length L and so the height h. Samples move out horizontally, not square to the wall, so the rims stay flat on the bed; L / h makes up the difference, and the wall is still t thick measured through it. A taper too steep for L has no solution and is refused.