Sarah Clarity Studios

Chapter 1: Fins, Radiators, Grills & Louvers

Created by Sarah Choi (prompt writer using ChatGPT)

Fins, Radiators, Grills & Louvers — Cooling, Vents & Thermal Language in Mecha Design

Thermal design is one of the fastest ways to make a mecha feel real. You can have perfect actuators and believable transmissions, but if the machine has nowhere to put its heat, it starts to feel like a toy. Cooling features—fins, radiators, grills, and louvers—are not just “greeble.” They are the visible language of energy use. They tell the audience what runs hot, what must breathe, what is protected, and what will fail if airflow is blocked.

This article is written equally for mecha concept artists on the concepting side and on the production side. For concepting, the goal is to build a consistent thermal story that supports silhouette and faction identity without clutter. For production, the goal is to make cooling believable and buildable: clear intake/exhaust logic, reasonable placement, protection from damage, and shapes that will hold up in 3D, LODs, and gameplay cameras.

Thermal language has three pillars: heat generation, airflow, and heat rejection. Fins and radiators are about rejection. Grills and louvers are about controlled airflow and protection. When these elements feel intentional, your mech reads like a designed system.

Why thermal language matters for mecha readability

Heat is story. A mech that runs hot implies power, strain, and risk. A mech that stays cool implies efficiency, premium engineering, or restrained output. Thermal features communicate these traits instantly.

Thermal language also helps players and viewers understand function. Vents near joints suggest high-power motors or gearboxes. Large radiators on the back suggest a reactor or engine. Vented forearms suggest tools or weapon heat. Even if the game never simulates heat, your depiction makes the machine feel plausible.

In production, thermal features become practical design anchors: they guide material choices (metal vs polymer), give believable areas for wear (soot, discoloration), and provide modular parts that can be reused across units.

Heat sources: decide what’s hot before you design vents

Cooling design starts with a heat map. Ask which systems generate heat in your mech.

Common heat sources include power plants (reactors, turbines, engines), electric motors and gear reduction at major joints, hydraulic pumps and fluid coolers, weapon systems, avionics/control computers, and braking surfaces. Even “muscle-mimic” systems have heat if they involve high-energy actuation or rapid cycling.

For concepting-side artists, you can sketch a simple heat map layer: warm zones (high heat), moderate zones, and cool zones. Then place your thermal features where they support that map.

For production-side artists, heat mapping helps prevent random vent placement. It also helps teams plan emissive effects, heat shimmer, VFX, and damage states consistently.

The three heat rejection modes: conduction, convection, radiation

You don’t have to be technical, but knowing the three modes of heat transfer helps your shapes make sense.

Conduction is heat moving through solid structure. This supports designs where heat is carried to large panels or fins. Convection is heat carried away by moving air (or fluid). This supports vents, fans, grills, and louvers. Radiation is heat emitted as energy from hot surfaces. This supports designs that show exposed hot plates, glowing edges, and radiator-like surfaces.

Most mecha cooling is a mix. A believable depiction often shows a conduction path (heat sinks and spreader plates) feeding a convection system (radiators and airflow). Radiation is the “high drama” layer you can use for style, especially on high-output units.

Fins: heat sinks as silhouette rhythm

Fins are the classic “this runs hot” cue. They imply surface area and airflow contact. In silhouette, fins create a comb-like rhythm that can unify a design if you repeat it consistently.

Fins read best when they are placed on parts that plausibly carry heat: motor housings, power cores, exhaust zones, and electronics bays. Small fins on tiny panels can look decorative; fins feel believable when they have a clear base (a solid block that the fins grow from) and a clear orientation (aligned to airflow).

In concepting, fins are a strong faction motif. A rugged faction might use thick, widely spaced fins that look cast or welded. A premium faction might use tight, precise fins that look machined. An alien faction might use organic fin ribs that still imply direction and heat flow.

In production, fin density matters. Extremely thin fins can be expensive to model and can shimmer at distance. You can design “implied fins” by using thicker fins, fewer repeats, or a patterned grill texture that suggests finning without requiring full geometry.

Radiators: big thermal statements and believable placement

Radiators are large, purposeful cooling surfaces. They imply the mech has serious power output and a system to reject heat.

Radiators can be depicted as panel arrays, fin stacks, or grid surfaces. They often read well on the back, shoulders, calves, or along a spine—places where surface area is available and where airflow can be managed.

A radiator should feel like it has a job and a vulnerability. If it’s exposed, it reads high performance but fragile. If it’s protected behind armor louvers or grills, it reads military and survivable.

For concepting-side work, radiators are a great way to communicate role. A siege or heavy unit may carry large protected radiators. A scout unit may have smaller integrated cooling with fewer exposed surfaces.

For production-side work, radiators should be designed as modular assemblies: repeating panels, consistent frame thickness, and clear mounting points. This makes them reusable and easier to swap across variants.

Grills: airflow with protection and readability

Grills are your “this intakes or exhausts air” cue. They also communicate protection: you can’t leave important internal components open to debris.

Grills read best when they sit over a volume that feels hollow or functional. A grill floating on a flat plate looks like decoration. A grill bridging a recessed cavity reads like an intake.

Design grills with a clear directionality. Vertical slats can imply downward airflow. Horizontal slats can imply side intake. Honeycomb patterns imply filtration and strength. Coarse grids read rugged and industrial. Fine meshes read premium and precise.

In concepting, grill patterns can become a faction signature. Choose one or two core patterns and repeat them at major intakes.

In production, grill patterns must survive LOD and distance. Fine mesh can turn into noise. A common strategy is to model a coarse grill in geometry and imply fine mesh with a texture underneath.

Louvers: controlled airflow and “intentional engineering”

Louvers are slats that control airflow and protect internals. They are one of the strongest “real machine” cues because they imply the designer thought about direction, water ingress, and debris.

Louvers are especially useful when you want vents on armored units without exposing fragile radiator surfaces. A louvered intake can be placed on a shoulder or torso and still read like a protected breathing system.

Louvers also carry a style message. Sharp, stepped louvers read aggressive and military. Smooth, integrated louvers read premium. Large, dramatic louvers read high-performance and “racing” aesthetics.

In production, louvers are friendly because they are readable shapes that don’t require super-fine geometry. They also provide great surfaces for wear and dust buildup.

Intake vs exhaust: the airflow story that makes vents believable

A big believability win is to imply an airflow story: air comes in somewhere and leaves somewhere else.

You don’t need to draw a full duct system. You do need to avoid the “vents everywhere” problem. If every surface is vented, nothing feels purposeful.

A helpful depiction approach is to designate a few main intakes (often cooler, cleaner-looking areas) and a few main exhausts (often dirtier, heat-stained areas). Intakes often have filtration cues (mesh, honeycomb). Exhausts often have heat cues (soot, discoloration, heat shimmer, glowing edges for extreme heat).

For concepting-side artists, this airflow story helps composition: intake shapes can be calmer; exhaust shapes can be more aggressive. For production-side artists, it helps place VFX and materials logically.

Heat cues beyond shapes: discoloration, soot, and emissive language

Thermal language is not just geometry. It’s also surface treatment.

Heat-stained metal can show subtle rainbowing or darkening near exhausts and hot housings. Soot and dust collect differently around vents: exhaust vents can stain outward; intakes can show dust accumulation at edges.

Emissive can be used carefully. If every vent glows, the mech looks like a toy. If one or two high-output zones glow (reactor seams, high-power exhaust, weapon cooling), it reads like controlled power.

For production, these cues can be layered as decals and material masks, giving teams adjustable intensity across skins, environments, and damage states.

Role-based thermal design: what your cooling says about the unit

Cooling language can reinforce gameplay roles.

A heavy or siege mech may have large radiator banks, thick fins, and protected louvers—suggesting sustained output and heat management. A fast striker may have smaller, more integrated cooling with directional vents—suggesting burst output and fast movement. A stealth unit may minimize exposed vents and use hidden intakes with baffled louvers—suggesting thermal management and signature control. A utility or support unit might show external cooling packs and serviceable radiator modules—suggesting uptime and repair culture.

This is useful in concepting because it ties visuals to function. It is useful in production because it provides consistent read across a roster.

Concepting-side workflow: build thermal motifs early

A strong concepting approach is to choose a thermal motif and apply it consistently. For example, “comb fins on all motors,” “louvered shoulder intakes,” and “radiator spine panels.”

Start with big shapes first: where are the radiators, where are the intakes/exhausts? Then add mid-level cues: grill pattern, louver rhythm, fin direction. Then add micro details: bolts, seams, warning labels.

If the design becomes noisy, pull back to the three-layer hierarchy: big blocks and stripes for distance, icons and labels for mid distance, fine print for close-ups.

A helpful sheet element is a small “thermal map” callout: a color-coded or shaded overlay that shows hot zones and airflow directions. This tells the story without requiring more geometry.

Production-side workflow: buildability, modularity, and LOD

In production, thermal features should be designed as assemblies. Radiators can be modular panel arrays. Grills and louvers can be standardized across multiple units. Fin blocks can be reused on motor housings.

Avoid ultra-fine geometry where it will shimmer or explode poly budgets. Prefer readable, chunky shapes that can be supported by textures at distance.

Plan LOD behavior: at far distances, fins and small grill holes will collapse into texture. Your design should still read through silhouette and large vent shapes.

Also consider collision and gameplay readability. Large protruding radiator fins on limbs may snag or break silhouette clarity. Sometimes the best choice is to keep high-density cooling on the torso/back where it’s protected and readable.

Common depiction mistakes and fixes

A common mistake is vents with no volume behind them. Fix it by recessing the vent area or showing a cavity shadow.

Another mistake is “vent spam.” Fix it by defining primary intakes and primary exhausts and keeping other surfaces quiet.

Another mistake is fins with no direction. Fix it by aligning fins to an implied airflow direction and giving them a clear base block.

Another mistake is putting fragile radiators on high-impact edges with no protection. Fix it by adding louvers, grills, or armor skirts—or by moving radiators to safer surfaces.

A paragraph-form thermal pass before you finalize

Before you finalize cooling design, ask: have you identified the major heat sources and placed the strongest thermal cues there? Do you have an airflow story with a few clear intakes and exhausts? Are fins, grills, and louvers oriented and placed in a way that implies controlled flow and protection? Do your cooling features match the unit’s role and faction engineering culture? And will the shapes survive production constraints—LOD, poly budgets, and readability at gameplay distance?

If the answer is yes, your thermal language will feel like a designed system rather than decorative texture.

Closing: thermal language is the visible cost of power

Fins, radiators, grills, and louvers are how a mecha shows that power isn’t free. They communicate where energy is being spent, where airflow must exist, and where heat must go. For concepting-side artists, thermal motifs add function, story, and faction identity while strengthening silhouette. For production-side artists, thermal cues create buildable assemblies, predictable material behavior, and clear zones for VFX and damage.

When your cooling feels intentional, the whole mech feels more believable—because it acknowledges the simplest truth of machines: everything powerful gets hot.