The 3D Handbook
Part 4 — Modeling
Chapter

Environment modeling

Read these pages in order, or jump to the one you need.

  1. Modular kitsTopicSets of environment pieces built on a shared grid so they snap together into many different spaces. How Bethesda, id and others design, test and vary them.
  2. Glue piecesKey termKit pieces whose job is to join other pieces, cover gaps at odd angles and bridge different kits. Bethesda built whole "glue kits" for this.
  3. Showcase (warehouse) mapKey termA test level that lays out every asset, kit piece or material in one place, so the team can check scale, consistency and quality in the engine before the content spreads across levels.
  4. Grids and metricsTopicThe measurements a game is built around (player size, jump height, door width, corridor width) and the snapping grid that keeps every piece consistent with them.
  5. Gym levels and metrics mapsKey termDeveloper-only test maps that lay out doors, stairs, jumps, ledges and slopes at measured sizes, so designers and artists can feel the player's metrics before building real levels.
  6. KitbashingTopicBuilding new assets or spaces by recombining existing parts, from film model kits to KitBash3D packs and mixed modular kits in Skyrim. Fast and legitimate, with honest-credit and consistency pitfalls.
  7. Hero assets, props and fillerTopicHow environment teams sort assets by importance: a few hero assets that anchor a place, secondary props that make it believable, and cheap filler that is reused everywhere. Where to spend detail, and where not to.
  8. Modeling rocks, trees and terrain piecesTopicHow environment artists build the natural parts of a game world (rocks, cliffs, embankments, caves and trees) as reusable, instanced pieces that sit on terrain, with examples from The Last of Us Part I and The Witcher 3.
  9. Collision meshesTopicThe simplified, invisible shapes that physics and the player actually touch. How to build them from boxes, capsules and convex hulls, and how Unreal, Unity and Godot import them.
  10. Convex hullKey termThe tightest shape with no dents that wraps a mesh, like a rubber band or shrink-wrap. Physics engines use convex hulls as cheap, reliable collision; concave objects need several.
  11. Convex decompositionKey termSplitting a concave mesh into a set of convex pieces so a physics engine can collide with it cheaply. How V-HACD, CoACD and the Unreal, Unity and Godot tools do it, which settings matter, and when to build the pieces by hand.
  12. Player collision capsuleKey termThe invisible pill shape that represents the player in the physics world. Its radius, height, step height and slope limit decide every door width, stair and ramp in your levels.