Chapter 3: Photo & Diagram Studies

Created by Sarah Choi (prompt writer using ChatGPT)

Photo & Diagram Studies (Orthographic Overlays, Part Labels)

Photo and diagram studies convert messy reality into clean, teachable geometry. For prop concept artists, they are the bridge between primary research and production‑ready documentation. When you trace orthographic truth from field photos, annotate part names, and diagram how components move and wear, you remove ambiguity for yourself in the concept phase and for your teammates in modeling, rigging, and look‑dev. This article details a practical, ethical, and production‑minded workflow for turning photographs into reliable orthographic overlays and labeled diagrams that hold up under camera scrutiny.

A good study begins with intent. Decide whether you are extracting proportion truth, interaction logic, or surface language. Proportion studies favor corrected, orthographic‑like views and visible scale references. Interaction studies favor sequences and arcs. Surface studies favor controlled lighting and macro detail that reveals edge behavior. Knowing which truth you are chasing determines how you shoot, how you correct distortion, what you trace, and how you label.

Fieldwork matters because it gives you control over viewpoint and scale. Aim to capture each subject at three distances: a context photo that shows how the prop sits among other objects, a three‑quarter mid‑shot that reveals silhouette and mass ratios, and closeups of joints, fasteners, and wear. Use a modest focal length that minimizes distortion—35 to 50 mm on full‑frame—and keep the camera height consistent with the object’s functional horizon. Include a scale marker in at least one frame: a ruler, a calibration card, or a common module such as a credit card. Photograph orthogonal faces as squarely as possible to reduce the correction effort later.

Photo correction is the step that makes tracing honest. Before you draw, de‑skew images so parallel edges are truly parallel. Use perspective guides to align verticals and horizontals, and apply lens profile corrections to remove barrel or pincushion distortion. If the subject is a planar face, a simple four‑point warping to a rectangle can approximate an orthographic projection for that face. If the subject is volumetric, assemble multiple corrected views rather than forcing a single photo to lie about depth. The goal is not to produce a forensic blueprint but to remove avoidable bias so your proportion reads survive into modeling.

Orthographic overlays translate corrected photos into measurable drawings. Start with centerlines, ground planes, and reference axes. Drop plumb lines from known edges, use equal‑division steps to find symmetry, and mark key inter‑part distances. Trace only what contributes to silhouette and function at first; small screws and fillets can wait until the big masses are truthful. Once the primary blocks are placed, step in the principal chamfers and radii that define highlight behavior at a distance. Add section ticks where thickness matters, such as handles, guards, and housings. The overlay should remain readable at 25–50% scale, which forces economy of line and prevents clutter.

Part labels turn lines into knowledge. Name components in plain language first—handle, latch, shutter—then, if relevant, include technical terms in parentheses for team searchability. Place labels on consistent sides of the sheet and connect them with straight leaders that avoid crossing critical geometry. If a part moves, include its range of motion as a small ghosted silhouette and label the start and end positions. If a part is standardized—thread type, pitch, rail slot—record the standard rather than guessing. Proper labels let production swap a guess for a known module, which accelerates modeling and ensures future compatibility across props.

Motion and state diagrams teach behavior. Most props live in at least two states, such as stowed and ready. On a single page, show the silhouette delta between these states without relying on color. Use simple arrows with tails that respect hinge axes and slide rails. Indicate locks and interlocks visibly by showing interference geometry rather than decorative icons. If a sequence is required, stage frames left to right with minimal overlap so the eye can follow time naturally, and annotate any prerequisites that are physically obvious, such as “lift tab before sliding.” This approach doubles as a safety read and a rigging guide.

Surface and wear studies complement the hard lines. After orthos are set, collect controlled photos of edges and planes under raking light. Draw small swatches that record how highlights break at chamfers, how micro‑roughness blooms on plastics, and where grease and hand oils polish handles. Tie each surface observation to a geometry feature on the overlay. These studies prevent over‑texturing and help look‑dev place detail where it will survive the gameplay camera instead of where it only looks good in a close render.

Collections become powerful when standardized. Store each study as a set: the corrected base photo, the orthographic overlay, the labeled diagram, and any motion or surface inserts. Use a consistent canvas size and grid so teams can compare studies at a glance. Embed metadata directly into the file or its sidecar: location and date of capture, focal length, estimated dimensions, material family, and a short note about function. Over time, this consistency turns your folder into a searchable library instead of a scrapbook.

Ethics underpins the value of your references. Obtain permission when photographing on private property or around proprietary equipment, and avoid capturing faces, badges, or sensitive information. Respect museum rules on photography and reproduction; in some cases, sketching is allowed while high‑resolution photography is not. Attribute sources when you rely on archival imagery, and track license terms. For living cultures and sacred objects, prefer observational drawing over close photography when access is limited, and consult with cultural experts before abstracting ornament or ritual mechanisms into fictional designs. Ethical discipline prevents legal and cultural harm and improves the credibility of your work.

Production realities should shape how you draw and label. Remember that modelers will use your overlays to build volumes and that riggers and animators will derive hinge axes and constraints from your motion diagrams. Include clear scale references on the page, either as numeric callouts or as a dimensioned bar. Mark non‑negotiable silhouette edges and minimum thicknesses that must survive down‑res and LOD transitions. If a bevel is essential to the read, specify its screen‑space target at common camera distances so the highlight band remains visible after optimization. Practical notes like these carry your study beyond the concept wall and into the game.

Review and testing keep the studies honest. Print the overlay at a reduced size to simulate gameplay distance and confirm that the silhouette and major edges remain legible. Flip the page horizontally to spot proportion biases you have stopped seeing. Ask a teammate unfamiliar with the object to explain how it works using only your diagram; confusion reveals missing arrows or mislabeled parts. Where possible, build a quick low‑poly blockout from your own overlay and drop it into a test camera; anything that breaks in three dimensions should be corrected in the drawing rather than left for production to discover.

Photo and diagram studies are not glamorous, but they are the fastest way to acquire design instincts you can trust. They train your eye to see measurable proportion, your hand to prioritize functional edges, and your mind to communicate motion and states without relying on text. When your overlays are clean and your labels describe real behavior, every downstream decision—from silhouette exploration to shader tuning—becomes faster and more confident. The payoff is cumulative: a library of disciplined studies becomes a silent mentor that raises the floor of your entire project.