fabrication
Practical fire effects in stop motion
Miniature set
Definition
Practical fire effects are in-camera combustion events -- flames, sparks, embers, glowing trails -- photographed frame by frame in the same exposure as the puppet or set they light, rather than added digitally in post.
Overview
Practical fire effects are combustion events -- flames, sparks, embers, glowing trails -- photographed for real, frame by frame, in the same exposure as the puppet or set they light, rather than generated or painted in afterward. The craft argument for choosing this over digital fire is continuity of light: a real flame throws real, physically correct light onto the puppet and set around it in the very frame it was shot, so there is no seam between practical performance and simulated element for a compositor to hide.
BBC Creative's 2026 Winter Olympics opening film, "Trails Will Blaze" (directed by Yannis Konstantinidis at the London studio Nomint, with BBC Creative director Justin Bairamian), is a documented worked example. The film animates 700 individually 3D-printed puppet athletes moving frame by frame across a scale model of the Dolomites, trailing real fire the whole way. Fourteen distinct combustion techniques were developed and supervised by the specialist pyrotechnics house Armoury FX (SFX supervisor Matthew Strange). Wherever a flame would actually touch the set or a puppet, standard set-dressing materials such as foam and cotton were replaced with heat-resistant substitutes -- kiln lining among them -- and the production ran weeks of dedicated pre-production burn testing to settle combustion behaviour, camera exposure and lighting balance before a single animation frame was shot.
Because a continuous burn rarely survives the time a frame-by-frame stop-motion setup needs between exposures, fire and puppet performance were often captured as separate practical passes on the same locked-off camera and set, then combined afterward. The compositing step here is closer to the multi-pass logic of Rig removal than to conventional VFX fire generation: nothing in the flame layer is synthetic, so the only work left is registering the practical passes to each other, not manufacturing the fire itself.
The discipline that separates this from ordinary on-set pyrotechnics is that every frame the audience sees originated from an actual combustion event, photographed under animator-controlled, frame-by-frame exposure -- the same discipline that governs any other practical element in a stop-motion frame. That discipline costs schedule: burn tests, material substitution and a dedicated SFX crew all sit upstream of animation and have to be budgeted alongside puppet fabrication, not bolted on in post the way digital fire can be.
Workflow
- Identify which shots' story value depends on the fire reading as real, and budget a specialist pyrotechnics crew alongside the puppet-fabrication schedule from the start -- practical fire cannot be added later the way CG fire can.
- Replace any standard set or puppet material that will be near a flame with a heat-resistant substitute (for example kiln lining in place of foam or cotton) before burn testing begins.
- Run dedicated pre-production burn tests, independent of animation, to settle combustion behaviour, camera exposure and lighting balance for each fire type the film needs.
- Where a continuous burn cannot be held frame by frame, shoot the fire and the puppet performance as separate practical passes on the same locked-off camera and set.
- Composite the passes so the flame stays visually anchored to the puppet or set it lights or trails, correcting only registration and exposure -- never regenerating the fire itself digitally.