ThreeJS Selective Unreal Bloom shows off an animated sci-fi engine — a detailed "Primary Ion Drive" model whose hot, glowing core blazes with a soft cinematic halo while the rest of the hull stays sharp.
How it works. The model is drawn through an effect composer that lays an Unreal-style bloom pass over the rendered frame. Bloom works from a brightness threshold: only pixels brighter than the cut-off — here the emissive engine parts — are picked out, blurred across several progressively smaller buffers and added back as a glow, so the light appears to bleed selectively from just the brightest surfaces. ACES filmic tone mapping then compresses the high dynamic range into natural on-screen colour, while the model plays a looping animation throughout.
How you interact:
- Orbit the model — drag to rotate and zoom within a fixed distance range so the engine stays framed.
- Threshold — raise or lower which brightness levels are allowed to glow, changing how selective the bloom is.
- Strength and radius — sliders set how intense the glow is and how far it spreads.
- Exposure — adjusts the overall tone-mapped brightness.
- Full screen — fills the display.
A self-contained three.js post-processing demo, rendered live on the Switch GPU and running fully offline.