Chapter 3: Heavy Vehicles

Created by Sarah Choi (prompt writer using ChatGPT)

Heavy Vehicles for Vehicle Concept Artists — Land Vehicles: Wheeled

Heavy vehicles are the muscle and backbone of a world. They move goods, bring help, and carry armor where it needs to be. Designing them asks for a different mindset than bikes or passenger cars: payload and mission dictate proportion, structure, and equipment first, and styling lives in service of those truths. For vehicle concept artists—both on the concepting side and the production side, across indie speed and AAA scale—this article frames haulers, fire & rescue, and armored vehicles through proportion, chassis, drivetrains, equipment, and camera reads. It also translates those decisions into practical deliverables that downstream teams can build from without guesswork.

Heavy vs. Light: what changes

Bikes place the human at the center of dynamics, and cars balance occupants with aesthetics. Heavy vehicles start with mission, payload, and uptime. Proportion is set by wheelbase steps, axle count, frame depth, and equipment envelopes. Turning circles and approach/departure angles are negotiated against legal limits and mission geometry. Weight distribution, suspension selection, tire size and count, and braking capacity scale with gross vehicle weight rating (GVWR). In concept exploration, your first thumbnails should lock load blocks before you decorate: a 10‑ton tank of water, a pallet grid, a protected crew cell. Production then measures these volumes, pins hardpoints, and protects service access.

Chassis & drivetrains at scale

Heavy vehicles use ladder frames or modular spaceframes with cross‑members sized to carry bending moments from concentrated loads. Axle counts (4×2, 6×4, 8×4, 10×4, etc.) determine wheelbase steps and turning behavior. Live axles with leaf springs or air springs dominate for durability and leveling; independent suspensions appear in specialty and high‑mobility roles. Steering can be single or dual axle; some extreme roles add rear‑axle steer. Braking is air‑assist with large drums or discs; retarder systems add downhill control. Drivetrains can be diesel/automatic, series or parallel hybrids, fuel‑cell electrics, or BEV with e‑axles; packaging shifts tank/battery locations, cooling stack sizes, and service corridors. Cutaways should make these choices explicit: frame rail depth and hole pattern standards, cross‑member spacing, axle modules, prop (or HV bus) paths, cooling cores, and PTO (power take‑off) locations for pumps or hydraulics.

Haulers: freight, dump, mixer, and special moves

Freight tractors and trailers (tractor–semi) are proportioned around kingpin location, fifth‑wheel height, and legal length/weight. Tractors show a long frame with sleeper or day cab, generous radiator, charge‑air coolers, and aero fairings. Trailers telegraph cargo type: box (smooth sides, rear roll‑up), reefer (condenser unit), flatbed (stake pockets, tie‑down rings), tanker (cylindrical with baffles), and lowboy (dropped deck for heavy equipment). Concept‑side silhouettes should emphasize module truth: cab, frame, fifth wheel, tractor axles; then trailer type and axle groupings. Production orthos lock kingpin–axle spacing, deck heights, landing gear, swing clearance, and bridge law spacing where relevant. Camera reads must keep tractor–trailer articulation visible and taillight/marker logic clear at distance.

Dump trucks read as large front axles, deep frames, and a dump body with high sidewalls and a tailgate hinge. Center of gravity shifts dramatically when raised; cylinder geometry and pivot placement must be honest in callouts. Frame reinforcement, body subframe, and hoist cylinder mounts become the silhouette language, with stone guards and fender liners that sell abuse tolerance. Production packages should provide hoist stroke, tip angle, and load/CG envelopes, plus tailgate latch types (barn, high‑lift) and bed liner details.

Concrete mixers telegraph drum volume, center of mass, and water/additive systems. The drum’s helix pitch and direction tie to load/unload; its support frame, drive gearbox, and chute stowage define silhouette anchors. Access ladders, wash‑down hoses, and chute swing arcs are gameplay and animation beats. Production callouts must show drum centerline, baffle geometry, gearbox ratios, water tank volume, and chute clearances.

Special haulers—car carriers, logging rigs, heavy‑haul lowboys—are defined by load interface. Car carriers display adjustable decks with hydraulic cylinders and safety chocks. Logging rigs show bunks, stakes, and load binders. Heavy‑haul uses multi‑axle dollies, goosenecks, and removable necks; proportion reads in axle packs and deck drops. Concept should stage load choreography; production must pin hydraulic travel, chain/cable paths, tie‑down hardpoints, and legal lighting.

Fire & rescue: time, access, and redundancy

Fire and rescue fleets are mission theaters on wheels. Pumpers/engines wrap a water tank (500–1500 gal typical), a pump module, and hose beds around a cab. The pump panel is a control wall—valves, gauges, intakes, discharges—and defines a strong mid‑ship read. Hard suction hose storage, ladder racks, and compartments with roll‑up doors and pull‑out trays express access under stress. Lighting and siren packages are visibility commitments: roof lightbars, grille lights, scene lights, rear arrows. Concept silhouettes should prioritize cab height/width, pump module volume, ladder stowage, and compartment rhythm; production orthos lock tank volume, pump capacity and intake heights, and ground ladder clearances.

Aerials (tillers, platforms) hinge on boom geometry. Tillers have steerable rear trailers; platforms carry baskets. Booms telescope and articulate; outriggers deploy with large ground contact pads. The silhouette is boom + outrigger geometry + compartment rhythm. Production callouts must state outrigger spread, pad size, deployment arc, boom sections, working height, and ladder rung spacing so rigging and physics can stage safe, believable operations.

Rescue/EMS vehicles favor fast access, clean interiors, medical storage, power and oxygen systems. Box bodies on cutaway vans or medium trucks place side and rear entries with lift assists or ramps; interior layouts must accommodate stretchers, attendants, and equipment. Exterior shows scene lighting, high‑visibility livery, and traffic management. Production packages need interior height, stretcher path and load height, O2 bottle mounts, electrical isolation, and washable material specs.

Wildland and airport rigs adapt for terrain or special hazards. Wildland brush trucks show skid units, hose reels, and high clearance with brush guards and pump‑and‑roll capability. Airport crash tenders showcase high‑capacity pumps, foam systems, roof/bumper turrets, and low‑pressure/high‑volume tires. Concept should emphasize terrain or hazard fit; production should specify foam ratios, turret traverse/elevation, and approach/departure angles.

Armored vehicles: protection, mobility, and perception

Armored trucks and cars in civilian settings protect cash, VIPs, or cargo; military MRAPs and APCs protect crews against firearms, shrapnel, and mines/IEDs. Protection levels dictate armor thickness, material (steel, composites, ceramics), and geometry (slopes, deflection, blast vents). Mobility chooses axle counts, tire types with run‑flats, beadlocks, CTIS (central tire inflation), and suspensions that survive weight and terrain. Perception and comms add camera turrets, sensors, antenna farms, and signal lighting under blackout conditions.

For armored cars (VIP/security), the silhouette must still read as plausible civilian architecture while hiding ballistic glass thickness, door hinge reinforcements, and subtle ride height increases. Drivetrains need up‑rated brakes and cooling. Doors gain lift assists and stronger latches. Production callouts must state glass thickness and weight, hinge axes, open angles, and emergency egress.

Cash‑in‑transit (CIT) vehicles show box bodies with vault doors, interlocks, and camera domes. The rear silhouette is dominated by security doors and step geometry; sides show small, high windows. Production packages should include interlock logic diagrams, vault wall cross‑sections, and panic hardware.

MRAP/APC silhouettes wear V‑hulls or blast deflectors, high ground clearance, modular armor tiles, and gunner or remote weapon stations. Interiors show energy‑attenuating seats and harnesses, with hatch arcs and ramp deploy forming key animation beats. Production must lock blast geometry, seat hardpoints, center of gravity, and escape routes. Camera reads must preserve friend/foe marking logic and aimable light signatures.

Proportion & silhouette: heavy truths

Heavy vehicles read through block hierarchy: cab (crew and controls), mission module (tank, pump, cargo, vault), and mobility (axles/tires/suspension). Get these big blocks right first. Wheel diameter scales with load; twin tires or super‑singles change the rhythm of wheel openings. Frame depth and ride height are honesty checks. Overhangs serve approach/departure or are traded for equipment. Negative space appears in ladder rack cutouts, outrigger bays, wheel arch daylight, and between cab and body modules; preserve these to keep silhouettes readable at distance.

Equipment & interface choreography

Heavy vehicles perform rituals—hooking a trailer, dumping, pumping, deploying ladders, rescuing, breaching—and each ritual requires clear interface geometry. Fifth‑wheel plate angle and kingpin height; dump hoist stroke and tailgate clearance; pump panel access and hose routing; ladder bed releases, ladder climb angle, and top‑rail safety; outrigger spread and pad stow; stretcher roll‑in height and rail locks. Concept art should stage these rituals in sequence frames; production should deliver callouts with dimensions, pivot coordinates, travel ranges, and keep‑out zones.

Materials, livery, and markings

Heavy duty means coatings, anti‑slip textures, reflective stripes, and placards. Fire & rescue use high‑visibility chevrons and block letters; logistics carriers use company marks, DOT placards, and conspicuity tape; armored fleets use low‑key palettes with agency seals. Materials emphasize powder‑coats, anodized aluminum, galvanized steel, and polycarbonate lenses. Production livery guides must include retro‑reflectivity, contrast ratios, font sizes by viewing distance, and UV/weathering expectations.

Camera reads & audio/VFX

Heavy silhouettes are large but often complex. Distance‑band boards should show marker/clearance light constellations, head/tail height cues, and mission beacons (lightbars, arrows, hazard strobes). VFX placements: dust and spray behind tandem axles, steam/foam at pump discharges, spark/slag at rescue tools, hydraulic mist at leaks. Audio: diesel clatter or inverter hum, air brake hiss, retarder whine, pump whir, siren wail sequences. Provide short sound/motion refs in research packets so mixing matches the machine.

Production deliverables

  • Metrics & mission sheet: GVWR band, wheelbase(s), axle count & spacing, frame rail depth/width, ride height bands (empty/loaded), approach/departure/breakover, turning circle/kerb‑to‑kerb, CG estimates (empty/full), tank/bed/box volumes, pump capacity, ladder reach.
  • Orthos (measured): Side/front/rear/top with frame lines, axle centers, fifth‑wheel/pump/hoist/pivot coordinates, outrigger bays, compartment bays, door/hatch arcs, lighting and marker placements.
  • Cutaways: Frame + driveline or HV bus + cooling + mission module internals (tank baffles, pump plumbing, drum helix, vault walls) and service corridors.
  • Exploded views: Subframes, axles, suspension modules, mission equipment, ladders/booms/hoses, with fastener and bushing logic and PTO interfaces.
  • Callouts: Hoist strokes and tip angles; pump panel valve types and sizes; hose diameters and stowage; ladder rung pitch; outrigger spread/pad size; stretcher load height; vault door interlocks; armor tile attachment patterns and replacement sequence.
  • Camera‑read boards: Far/mid/near day/night/fog/dust; emergency states (lights/sirens), dump/pump/deploy sequences.
  • Change log & kit list: Standardized hardpoints (frame hole patterns, PTO flanges, outrigger mounts), hose/cable couplings, ladder rail profiles, marker light families.

Indie vs. AAA cadence

Indie teams benefit from a single evolving mission canvas per vehicle: silhouette blocks + side ortho with frame/axle lines + a quick cutaway of the mission module + sequence frames for the key ritual. Validate in engine by driving a greybox around corners and through level bottlenecks; adjust wheelbase, axle placement, and overhangs early. AAA teams split by gate and consumer: platform & mission lock, layout lock, modeling kickoff, rigging & FX check, camera‑read sign‑off, and livery/marking QA, with versioned kits for axles, ladders, pumps, and outriggers so multiple vehicles share parts and behavior.

Concept vs. production mindset

Concept guards mission clarity: big blocks, obvious rituals, readable markers, truthful weight. Production guards buildability and service: frame holes line up, pumps/plumbing route without fantasy intersections, ladders deploy without clipping, armor swaps in tiles. Both protect safety envelopes—outrigger stability, egress routes, handholds/steps—and regulatory cues that players expect subconsciously.

Closing

Heavy vehicles are the world’s infrastructure made visible. When you design haulers, fire & rescue, and armored platforms from payload and ritual outward—and you encode those choices in orthos, cutaways, callouts, and camera‑reads—your fleets will feel inevitable. Players will read purpose in a glance; teams will build fast without contradictions. That is the difference between a cool render and a vehicle that belongs to a living, working world.