skate-3-rust-engine/mods/Skyline_Drive_Mod

Skyline DRIVE — Model Collision Repair 4.3.1

No separate collision assets

The car now uses skyline.glb for BOTH graphics and collision. Its existing skyline_mesh body node supplies the source triangles. The engine builds multiple convex parts at runtime and keeps them in RAM, under one rigid body with the existing authored mass, center of mass and inertia. No collision GLB, collision JSON, authoring exporter or embedded collision-point list is required or written.

The separate skyline_collision.glb, collision_geometry.json, and COLLISION_ASSET.md from 4.3.0 have been removed. Replace the previous mod folder rather than merging into it to remove those obsolete files as well. Keep only one enabled package with id examples.skyline.

This is not the old single hull pointed at a different file: type="model" uses the real triangle geometry, full scene transforms and Parry convex decomposition. The legacy type="mesh" API remains available for older mods but is NOT used here. Model options in Lua are max_hulls=32, resolution=96 and concavity=0.0025. These are approximation controls, not a promise of a millimetre-accurate surface. The runtime-generated result has not been measured or playtested in this environment. The first spawn can pause while cooking; unchanged respawns reuse an in-memory cache. Cache entries are invalidated by changed model bytes or options. No disk collision cache is made, so a new process cooks the first instance again.

The selected collision node is the rigid body mesh, not the separately animated wheel nodes. Tires retain the existing raycast-suspension/reduced-order tire physics, rather than being baked into the chassis or changed into rigid wheel bodies. The input scene/model units and geometry are not rescaled or overwritten.

Required engine update

Install the matching Model Collision Repair source update, then successfully rebuild BOTH game targets. An old installed executable cannot acquire native commands by replacing api.lua. This mod checks capabilities originating in the native VM BEFORE sending physics_debug, scene-node or model-spawn commands. The root SDK API remains version 2; named capabilities distinguish this extension.

Both multiplayer clients need the rebuilt engine and the same enabled mod files. The new object protocol transmits the resolved compound geometry, not a path to a required collision file. It does not transfer the visual GLB/audio assets or execute another player's Lua. Different package bytes are deliberately rejected.

Preserved features and controls

F10 spawns. E / controller Y enters or requests exit. R / Start resets. H toggles driving diagnostics. C / controller X changes camera. J toggles the actual solid colliders: green local, amber remote, cyan center of mass. The hull view draws the generated convex parts, not an unrelated display/proxy model.

Independent wheel spin, front steering and suspension animation remain enabled. Door entry radius remains 1.20 m. Safe exit requests outside, upright on-foot placement; blocked exit keeps occupancy. The five-second re-entry cooldown starts after confirmed exit. Camera, dashboard, audio, tire solver, engine, gearbox, clutch and aero settings are retained. Original visual and audio assets have not been changed. The existing hidden-driver presentation remains unchanged.

What was and was not tested

41 assertions passed using the actual updated Lua API/mod through Lua 5.4 and a test host. This includes rejecting partial/old native capabilities before queuing new commands, selecting the same render/collision GLB, wheel animation, exits, entry cooldown and debug commands. A 120-tick comparison produced the same submitted force/torque histories as the prior driving baseline for identical inputs. This is NOT proof of identical handling after collision geometry changes.

All 19 original GLB/audio/sound-bank assets are byte-identical. The render-body input has 17,123 source positions (8,489 after exact position welding), 19 primitives and 16,532 nondegenerate triangles. Those are source-model counts, NOT a measured cooked-hull output.

Rust compilation, the actual VHACD cook, Bevy rendering, native BoardWorld contact, Windows execution and two-client networking were NOT run here. The source repair includes Rust regression tests and validate_model, which runs the real cook, Rapier spawn and compact replication round trip on your machine without producing collision files. Use J and test roof standing/walking and vehicle impacts after successful compilation; no unconditional no-penetration claim is made.