A face piece is three crafts stapled together: sculpt a master, cast the piece, blend it onto skin. On this site the hands-on halves already have their guides, SFX Makeup owns everything that touches skin, and One Mold, Many Props owns the pour. This page is the bridge between them: the measurement, the planning math and the fit checks the app actually documents. And it says plainly what the app does not document: there is no sculpting tool in it, no skin-contact craft and no brand advice. The app carries the fit and the mix; the skin and the edges stay with the two guides, and the wall's Face paint & prosthetics shelf carries the approved how-tos for the eye training.
Every prosthetic fit starts with a profile, not a guess. The app's body profiles keep a Head & neck group of seven fields: head circumference, ear-to-ear width, cheekbone width, brow-to-back depth, chin-to-crown height, pupil distance and neck circumference, plus a Clearances pair of helmet-padding thickness and underlayer thickness. Two honest ways to fill them, straight from the app's own rules:
The app's own limit line is worth taping to the bench: perspective correction is valid only for the marked plane, it cannot recover hidden geometry, depth differences, curved anatomy, lens distortion or wrong landmarks, and there is no automatic card or anatomy detection. Compare photo estimates with physical measurements, every time.
The app has no clay and no sculpting surface, that part is yours. What it owns is the master's dimensions. The Scale & material impact calculator takes base and target spans in X, Y and Z and returns the three percentages, for a face piece scaled from a reference dome, that's the whole translation problem. Its caveat is the number-reading lesson in one line: volume scales by X × Y × Z, the area number applies to the XY projection (that's what scales sheet material, primer and paint), and "scaling alone cannot confirm a helmet's internal fit", the fit check is the next section.
The master rules come from the casting guide: seal porous surfaces (clay sticks otherwise), keep deep undercuts off a first mold, sloped walls and open shapes release cleanly, and mount the master in a small box with the detail side up. A printed master is the 3D-print guide's route. And if the piece is one of a pair, horns, ears, gems, that's the casting guide's whole argument: sculpt once, cast forever.
Two app tools plan the pour. The Silicone & resin mix tool takes the mold box (rectangle or cylinder), subtracts the master displacement, adds a waste allowance (its default is 10%), and splits Part A and Part B on the manufacturer's mix basis. Its permanent warning is the lesson: weight and volume ratios are not interchangeable, use the exact ratio, density, pot life and handling instructions for the material in your hand.
Behind it sits the Casting material library, a versioned snapshot of the manufacturers' own numbers, checked 2026-10-22, with the standing note that product instructions always take precedence over the snapshot. The face-piece-relevant lines, all at 23 °C:
| Material | Mix (weight · volume) | Pot life | Cure reference | Kind |
|---|---|---|---|---|
| Smooth-On OOMOO 25 | 100:130 · 1:1 | 15 min | 75 min | Tin silicone |
| Smooth-On OOMOO 30 | 100:130 · 1:1 | 30 min | 360 min | Tin silicone |
| Smooth-On Mold Star 15 SLOW | 1:1 · 1:1 | 50 min | 240 min | Platinum silicone |
| Smooth-On Dragon Skin 10 Medium | 1:1 · 1:1 | 20 min | 300 min | Platinum silicone |
The library also carries what it doesn't know. Alumilite Clear Slow's density and timing are marked unverified, and FlexFoam-iT!'s 15× expansion note insists the published 0.05 g/mL is the expanded foam's density, never the liquid's. Soft bits (straps, ears that flex) come from the casting guide's flexible rubber compound (1:1). The pour technique, thin, high, cure per data sheet at room temperature, is the casting guide's section, and the app's two-stage timer (working stage, then cure, with deadlines and optional alerts) carries it, with its own honesty: alerts are inexact and restart-after-reboot, and a timer never confirms cure; times depend on temperature, mass and mold. Demold-test a corner trim like the casting guide says.
For anything head-carried, face plate, half mask, full cowl, the app's mesh inspector is the try-on. Import an STL or OBJ (the ceiling is 48 MB and 200,000 triangles; all geometry stays on the device), and it renders the mesh with a parametric head scaled from your profile, your profile's head width itself takes the larger of your ear-to-ear and cheekbone measurements. Toggleable layers sit on top: a padding shell (default 10 mm) and a glasses/nose-bridge zone, because the piece has to clear them too. The checks say what they can: head/eyewear intersection checks supplement sampled section-by-section clearance, and open or branching sections come back inconclusive rather than guessed.
The mannequin's honesty is the quote to remember: "a parametric mannequin is a fit aid", hair, ears, facial details, flexibility, padding compression and tilted insertion need a physical test. If the piece goes over a wrapped layer, the app adds 2πt of circumference per layer (2t per diameter), underlayers count, and they're opt-in in the profile. And for full-head pieces the app's weight flag is a design advisory, not a medical rule: finished weight over 1,200 g draws a neck-fatigue warning and a suggestion to reconsider geometry and do a wear test.
The skin side is the SFX guide's contract, and it's worth repeating the spine of it here: cosmetic-grade or it doesn't go on; patch test anything new on the inner arm for 20 minutes; around the eyes, powder products only. Pros-Aide-class adhesive for prosthetic pieces, spirit gum for lace edges and light pieces, scar wax for flat-surface pieces blended with a damp fingertip, seal, then color. The realism rule is contrast, not product: recess the shadows, lighten the rims, and let a con's lights excuse going slightly too dark.
The rig behind the piece is this site's home turf, not an afterthought: lit prosthetics and visors follow the lab's mask painter + LED planners and the learning pages' double-diffusion rule for faces and visors; a mech brow or blink is the servo lesson; and if the piece performs with sound on your wrist, the gesture-chain guide is where the timing lives. For the paint, the lab's mask painter opens with a finished scheme painted on a dome and switches between a starter scheme and a metallic scheme — two browser rehearsals of a face piece's paint chain, each exported as a PNG the bench can follow while the real piece is on the table.
| On the face | Off with |
|---|---|
| Gelatin pieces | Warm water + gentle soak, peel slowly (bin it, not the drain) |
| Pros-Aide pieces | Adhesive remover or isopropyl myristate, never rip |
| Body paint around the piece | Cold cream or oil cleanse, then soap |
The app's default packing kit already expects this life: its starter lines include "Spirit gum & remover" beside hot glue sticks and cyanoacrylate, and every packing line can be assigned to a build element, so the face piece's removal kit travels with that costume's bag, not in a shared pile.
| Symptom | Cause | Fix |
|---|---|---|
| The photo-measured span came out small | The card corners weren't marked, or the span sits off the marked plane | Compare with a real tape before cutting anything; planar correction covers the marked plane only |
| The cast has foam in it | Whipped air, fast stirring or a splash | Pour thin and high; rest the mix 2 min; pressure pot if it keeps happening (casting guide) |
| The mix ran out mid-pour | Box volume minus master with no waste | The tool's waste default is 10%, leave it in for the first pour |
| The timer expired and it's still soft | A timer never confirms cure, times depend on temperature, mass and mold | Early-test a corner trim; room temperature and section thickness run the clock |
| The piece reads flat in con photos | Contrast, not chemistry, the shadows got painted over | Recess the middle, lighten the rim; let the paint go slightly too dark (SFX guide) |
| The helm stops over the mask | Layers add circumference, 2πt per wrapper, padding included | Run the profile's clearance fields; add the layers opt-in before sizing |