Chapter 3: Wearables — Watches, HUDs, Exo‑Accessories

Created by Sarah Choi (prompt writer using ChatGPT)

Wearables — Watches, HUDs, Exo‑Accessories (Tech & Devices)

Wearables sit on the boundary between prop and costume, touching skin, bone, and daily ritual. For prop concept artists, watches, head‑up displays, and exo‑accessories must read as both instruments and apparel, carrying comms, sensors, and power in ways the audience believes at a glance. This article frames wearables as small systems—structures, batteries, radios, optics, and data paths—equally useful to concept-side ideation and production-side handoff. If the device explains how it stays on the body, how it breathes heat, and where it talks to the world, it will feel real regardless of genre.

A watch begins as a circle of constraints. The underside is the truth surface where skin meets sensors; the topside is a stage for glass and bezel to perform identity. Watches read their role through case geometry and lug logic: a thin mid-case with crisp chamfers suggests corporate minimal; a tall case with guard towers and protruding screws suggests field duty; a cushion case with inset buttons hints retro durability. The strap is structure, not trim; quick-release bars, diver’s extensions, ladder perforations, and elastic loops tell a story about gloves, sweat, and urgency. For production, specify lug width, spring bar diameter, and strap thickness so teams can swap families without re-authoring silhouettes.

Comms live in the frame and must dodge biology. Bluetooth and UWB prefer polymer windows away from metal edges; LTE or sat bands justify ceramic rings or raised antenna arcs. If the watch claims water resistance, show double-lip gaskets, screw backs, and a distinct speaker membrane with a drainage notch. A believable microphone sits on a chamfer away from the wrist and pairs with a second pinhole to sell beamforming; a credible speaker fires laterally into a cavity that vents near the case wing. Exterior crowns and buttons need tactile differentiation so blind-find is possible during motion; a smooth crown for scroll and a knurled or guarded pusher for confirmation are legible even in a medium shot.

Sensors turn the underside into a lab. Photoplethysmography domes should sit proud enough to guarantee skin contact, ringed by a matte moat that kills stray light. Temperature sensors prefer a metallic puck that kisses the skin; ECG wants opposing electrodes separated across the case or on the bezel. GPS and magnetometers demand distance from steel, so raise the mid-case on polymer lugs or isolate with a ceramic island. For fiction that borrows arcane or exotic sensing, keep the same placement logic: crystal studs where real LEDs would sit, rune rings where electrodes belong, and thermal fins where heat actually exits. Production can separate the underside into clean materials stacks—clear lens, sensor dome, gasket, matte moat—so shader work can sell translucency and subsurface scatter.

Batteries dictate mass and cadence. Watches carry curved pouches or coin cells under the dial; heavy-duty models add strap cells inside thick elastomer to shift weight off the wrist. If hot-swap is part of the world, show latch bays with keyed tabs and tiny polarity glyphs; if wireless charging is the norm, emboss coil outlines and alignment dots onto the underside and echo them into docks and stands. Power ritual is story: a bedside puck becomes a nightly anchor; a rail-charged exo-sleeve says mission staging; a solar ring on a bezel whispers off-grid resilience. Production should specify charge pin pitch and magnet polarity so props can be shared across scenes.

HUDs bring optics into anatomy. A monocular boom must clear cheekbones, eyelashes, and helmets, while keeping the display within the eye box. A transparent combiner wants a thin wedge with AR coating that throws a faint green or purple sheen at oblique angles; a waveguide bar wants a thicker temple with discrete input and output gratings. The hinge stack sells durability: a base pivot for stow/deploy, a micro tilt for eye relief, and a telescoping arm for interpupillary adjustment. Cameras and depth sensors belong on the non‑occluded corners of frames; privacy shutters or mechanical irises can convey ethics without dialogue. Cable routing should be credible even on wireless variants—short service loops at hinges, strain reliefs at temples, and subtle polymer breaks for antenna windows.

Exo‑accessories translate device logic into the larger body map. Chest plates carry radios and batteries where lungs and armor meet; shoulder pucks can hold antennas and LIDAR where field of view is clear; forearm rails keep controls within glance and reach. The human envelope matters more than sci‑fi gloss: clavicle clearance for chest straps, elbow flex for forearm braces, neck rotation for collar mounts. Fasteners must tell how the user gets in and out—side-release buckles for speed, ladder locks for adjustability, twist cams for tool‑less clamping, and captive screws where security beats convenience. Pair every rigid brace with soft pads and vent cuts to make sweat and motion believable.

Thermal paths are the honesty layer across all wearables. Skin is a poor radiator, so hot components must push heat into air or structure. Watches and HUDs should show metal mid-frames acting as spreaders with low-profile fins hidden beneath tasteful breaks; exo units can display more aggressive heat sinks with castellation, heat pipes that suggest internal loops, or fabric chimneys that vent under capes and armor. If the fiction calls for silent operation, trade fan intakes for larger fin area and orient vents away from microphones. Let paint and patina tell thermal history: yellowing near exhausts, polished hot spots on crowns, and perspiration salt creep along strap edges.

Indicators and UI must respect the body’s attention budget. A watch face can carry a small triad of states—link, secure, low power—using restrained LEDs or bezel glyphs the camera can catch even when the screen is off. A HUD should convey horizon and alerts with minimal motion and prioritize contrast over color so it survives daylight. Exo‑accessories can move indicators onto the periphery: shoulder bargraphs for battery visible to teammates, chest icons for mode that sit below the chin, and haptic pips on straps that pulse distinct patterns for alerts. Consistent iconography across the wearable family lets the audience learn once and read everywhere.

Antenna language on the body is geometry and material. Polymer windows, ceramic patches, and flexible printed antennas prefer exposed, non-metallic surfaces, which means strap segments, shoulder paddles, and collar ridges are RF real estate. A paddle on a shoulder angled 15 degrees off vertical reads as MIMO or diversity; a loop stitched into a strap reads as near‑field comms for tokens; a small dome on a collar suggests GNSS or UWB. If stealth is doctrine, embed antennas in textile laminates and signal them with stitch patterns or embossed marks rather than visible whips.

Audio paths define social texture. Beamforming wants dual or triple mic clusters separated by 10–20 mm and protected from clothing rustle; bone conduction wants temple pads and spring arms that find cheekbones without pain; privacy wants short acoustic tubes from chest to collar. Speakers in watches must fire laterally and reflect off the wrist or bezel; exo‑speakers can vent forward with shallow waveguides so speech cuts through noise. Every audio channel deserves a corresponding visual or haptic indicator so users can operate under stress without staring at screens.

Materials and finish tie hardware to costume. Elastomer straps with shore hardness tuned for sweat and flex sit against skin; woven aramid and spacer mesh carry load against fabric; titanium and ceramic signal premium endurance with distinct highlights. Scratches tell truth: polished chamfers catch hairlines, brushed flats hide them, and bead‑blasted titanium ghosts scuffs as dull blooms. For production, separate shader groups by contact type—skin, fabric, armor—so grime and oil maps can be layered per surface. In fantasy reskins, keep the material logic intact through analogues—bone for ceramic, lacquer for polymer, leather for elastomer—and place wear where physics demands.

Fit and sizing are narrative grace notes. A too‑tight strap prints skin; a loose exo‑brace slips and polishes only the high points; a HUD with poor hinge geometry leaves the lens off center or forces the wearer to squint. Include micro adjustments the camera can understand: a numbered crown with detents, a ratchet sound on a strap ladder, a click stop on a HUD boom. Show how a teammate could help: a rear pull tab on a chest harness or a color‑coded tag that signals where to tug in an emergency.

Power and data ecosystems create family cohesion. Watches dock to pucks and travel bricks; HUDs seat into helmet cradles with keyed rails; exo‑accessories snap into vest buses with standard plugs. Trace cables truthfully with tie‑downs and service loops, avoid pinch paths at joints, and give every connector a mate with the same icon set repeated on chargers and tools. If wireless power or smart fabric exists, keep physical logic somewhere—alignment marks, stitching paths, status tags—so the audience isn’t left guessing.

Safety and compliance are visible world rules. Medical wearables need skin‑safe logos, quick‑release tabs, and sterile covers; military wearables need IFF marks, tamper seals, and zeroize hatches. Hazard glyphs belong near heat, pinch, and shock zones. If your fiction includes legal limits on augmentation, emboss permit badges or serial plates on external faces to give law and culture a foothold on the hardware. These are small props but potent narrative levers.

For concept-side iteration, explore silhouettes by anchoring to anatomy first. Sketch the strap and lug geometry on a wrist, the hinge arc of a HUD around an eye, and the brace path of an exo on an arm. Overlay modules—battery, radio, sensor—and shuffle until mass sits where the body can bear it. Paint patina maps early to decide where polish and grime will sell contact. Once the shapes read, add indicators sparingly and repeat an icon language across the family.

For production-side handoff, deliver parametric kits. Provide orthos with section profiles for cases and hinges, exploded views of sensor stacks and gasket seats, keep‑out volumes for skin and fabric, emissive IDs for LEDs and displays, and decal maps with a compact symbol lexicon. Include timing beats for animation and audio—crown push duration, HUD deploy speed, haptic pulse cadence—and list material targets for lookdev including IOR for glass, AR hue for coatings, polymer micrograin density, and sweat‑oil roughness overrides at contact patches. Offer fit variants for small, medium, and large anatomies sharing common mid‑frames so wardrobe and rigging can scale without new sculpts.

When a wearable shows how it grips, breathes, speaks, and feels, the audience will trust it before the UI even lights up. Treat the wrist, head, and limb as landscapes; let hardware follow those contours with honest power, RF, and sensor paths; and your watches, HUDs, and exo‑accessories will feel inevitable rather than invented.