Nebula Forge — Free Real-Time Space Background Generator

Make your own space backgrounds, right here in the browser. Move the sliders, hit Randomise until you like something, and save a PNG. Free, no signup, nothing uploaded — it renders on your GPU.

Forge renders stills. Want them moving? Nebula Motion Pack Vol.1, $9 is five seamless animated loops from this same raymarcher — the camera flies through one Z-periodic volume, so the last frame meets the first with no crossfade. It lives on the Vol.1 page. Forge itself stays free, always.

This is a real volumetric raymarcher, not a filter

Most "space background" art is 2D noise with a colour ramp. This marches a camera through an actual 3D volume of gas and dust, which is why the filaments have depth and the dust lanes genuinely occlude what is behind them.

• Ridged multifractal density — filaments, sheets and pillars instead of cotton wool
• Beer-Lambert extinction — dark lanes are real column density, not painted shadow
• Real nebular emission lines — H-alpha, O-III, S-II, mixed by local ionisation
• Blackbody star colour at genuine stellar temperatures, so hot stars are blue because 27,000 K is blue
• Three colour treatments — true colour, Hubble SHO narrowband (the gold-and-teal Pillars look, with SCNR green suppression), and HOO

Free to use

Anything you export is yours to use in personal and commercial projects, no attribution required. Please don't resell the exported images as their own asset pack.

Want them pre-rendered, layered and tileable?

The downloadable packs are rendered offline at full quality — 1920×1080, far more marching steps, the full CIE 1931 colour integral, and each background split into real depth slabs so parallax is geometrically correct rather than three separate images faked into it:

• Nebula Volumetric Vol.3 — 12 backgrounds, 5 depth slabs each
• Vol.1 and Vol.2 — 24 more, layered

Not AI generated

No image model involved. Deterministic physics and mathematics, reproducible from a seed — the seed is right there in the panel.

Found a look you like but need it at another resolution, or tiling vertically too? Leave a comment.