About Hidden3DImage

What this site is

Hidden3DImage is a free online studio for making autostereograms — the "Magic Eye" pictures that hide a 3D shape inside a flat repeating pattern. You type a word or choose a shape, pick a texture, set the depth, and the site renders a genuine single-image stereogram you can download as a PNG and share.

It is also a learning resource. The viewing guide teaches the parallel-viewing technique with practice drills, the science page explains the perception and the algorithm honestly and in plain language, and the gallery gives beginners tuned images to practice on — with an answer key.

How the generator works

Everything runs in your browser using vanilla HTML, CSS, JavaScript, and the Canvas API — no frameworks, no plugins, no server-side processing. The renderer uses the classic pattern-strip method used by printed Magic Eye posters: a seamlessly tiling strip of texture 104 pixels wide is repeated across the image, and the hidden subject exists only as tiny changes in that repeat distance. The shape is never painted onto the output; it lives purely in the geometry, which is exactly why it is invisible until your eyes fuse the pattern.

Because generation is fully client-side, your text and images never leave your device. That is not a marketing line — it is how the code is built, and you can verify it: the page makes no network requests during generation.

Why we built it

Stereograms were a genuine mass phenomenon in the 1990s — tens of millions of books and posters sold — and then quietly became a niche. But the underlying experience has not aged at all: the moment a shape rises silently out of visual noise is still one of the best "aha" moments perception has to offer. Most online tools for making them are either abandoned, buried in ads, or require uploads to a server. We wanted a version that is fast, private, pleasant to use, and honest about how the trick works.

Principles

• Local first. Generation never touches a server. Your inputs are yours.
• Real rendering. No pre-baked images pretending to be generated. The algorithm runs live, every time — including the gallery.
• Teach the trick. The illusion is more fun when you understand it, so the explanations are real explanations, not filler.
• Light and durable. Static pages, no dependencies, quick on a mid-range phone. The site should still work unchanged years from now.

Get in touch

Feature ideas, bug reports, classroom use, or just a stereogram you're proud of — we'd like to hear about it. Reach us through the contact page.