Roblox physics
Read ../../references/roblox-engineering.md. Inspect the authored hierarchy, assemblies, roots, anchoring, attachments, constraints, collision groups, and current ownership code before changing behavior.
Treat simulation as distributed and untrusted
- Decide network ownership at the assembly level as both a responsiveness and authority choice. Client ownership reduces input latency and server work, but the client can manipulate its simulation.
- Keep gameplay-critical assemblies server-owned when practical. For responsive player-controlled physics, assign ownership deliberately and validate server-observed position, speed, state transitions, and outcomes within game-specific tolerances.
- Reapply or release explicit ownership when seats, characters, tools, assemblies, or round state change. Anchoring and reconnecting parts can change the ownership model.
- Do not treat
Touched alone as proof of authoritative damage, collection, or completion. Confirm server-side identity, spatial plausibility, state, cooldown, and duplicate behavior; use an appropriate ray or swept spatial query for fast motion.
- Prefer attachments and constraints for simulated mechanisms. Apply forces or impulses to the intended assembly instead of fighting physics with repeated per-frame transforms or velocity assignments.
- Make collision groups and query filters explicit. Exclude the source assembly, validate returned instances and ancestry, and separate physical collision from detection when gameplay requires different rules.
- Bound active simulated assemblies, query frequency, and per-frame work. Measure server physics cost, replication, and mobile client behavior before optimizing.
Deliverable
State the assembly root, owner through each lifecycle state, authority checks, collision and query rules, constraint model, cleanup, and failure behavior. Verify pure hit-validation and state-transition logic locally. Give the user exact Studio checks for ownership visualization, multiple clients, latency, reset, and high-speed contact; never invoke the playtest through MCP.
1---2name: roblox-physics3description: Design or review Roblox assemblies, constraints, collision, hit detection, and network ownership.4---56# Roblox physics78Read [`../../references/roblox-engineering.md`](../../references/roblox-engineering.md). Inspect the authored hierarchy, assemblies, roots, anchoring, attachments, constraints, collision groups, and current ownership code before changing behavior.910## Treat simulation as distributed and untrusted1112- Decide network ownership at the assembly level as both a responsiveness and authority choice. Client ownership reduces input latency and server work, but the client can manipulate its simulation.13- Keep gameplay-critical assemblies server-owned when practical. For responsive player-controlled physics, assign ownership deliberately and validate server-observed position, speed, state transitions, and outcomes within game-specific tolerances.14- Reapply or release explicit ownership when seats, characters, tools, assemblies, or round state change. Anchoring and reconnecting parts can change the ownership model.15- Do not treat `Touched` alone as proof of authoritative damage, collection, or completion. Confirm server-side identity, spatial plausibility, state, cooldown, and duplicate behavior; use an appropriate ray or swept spatial query for fast motion.16- Prefer attachments and constraints for simulated mechanisms. Apply forces or impulses to the intended assembly instead of fighting physics with repeated per-frame transforms or velocity assignments.17- Make collision groups and query filters explicit. Exclude the source assembly, validate returned instances and ancestry, and separate physical collision from detection when gameplay requires different rules.18- Bound active simulated assemblies, query frequency, and per-frame work. Measure server physics cost, replication, and mobile client behavior before optimizing.1920## Deliverable2122State the assembly root, owner through each lifecycle state, authority checks, collision and query rules, constraint model, cleanup, and failure behavior. Verify pure hit-validation and state-transition logic locally. Give the user exact Studio checks for ownership visualization, multiple clients, latency, reset, and high-speed contact; never invoke the playtest through MCP.
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