Library boundaries — platform layer stack

Authoritative dependency law for Novolis libraries. Numeric spine: novolis-math, novolis-physics, novolis-simulation. Product spine continues through novolis-gaming and novolis-avalonia into apps.

`novolis-raylib` is not part of this stack — no package reference between Raylib and Simulation (either direction). Apps that need both wire them at the product layer.

There are no “Kit” layers in the platform (no GameKit, CadKit, LabKit packages). Product repos and hosts compose the stack directly.

Stack (dependency direction)

Math
  ↓
Physics
  ↓
Simulation
  ↓
Gaming (Novolis.Game.*)
  ↓
Avalonia (Novolis.Avalonia.*)
  ↓
Apps

Lower layers must not reference higher layers. Same-layer / peer facet refs are fine. Apps compose any combination.

Avalonia isolation: only Novolis.Avalonia.* libraries may take Avalonia / Avalonia.* package references. Math, Physics, Simulation, Gaming, Economy, Astro, Rendering, Raylib, Agent, Cad, Audio, etc. stay Avalonia-free. Product apps may reference Avalonia directly.

Enforced by Novolis.Analyzers.StackBoundaries (NOV2006, NOV2007) and scripts/verify-layer-boundaries.ps1.

`novolis-raylib` remains a separate graphics/input host — orthogonal to the spine (never ↔ Simulation).

Simulation is not a game engine. It is neutral orchestration: worlds, objects, systems, time, observation, recording, and replay. HexGame-style game ticks belong in Simulation and apps — not in Physics (see hexgame-authoritative-core.md).

One-line rules

`Novolis.Math.*` — space and numbers only

Repo: novolis-math

Math is one library family with facets (separate packages, same repo). Geometry and topology are parts of math, not separate platform layers or dependency tiers.

BCL type first — always, no exception

When the BCL provides a type, use it. Do not add Novolis duplicates.

Allowed Novolis types only where the BCL has no equivalent: Ray, Sphere, AxisAlignedBox, TriangleMesh, DenseGrid<T>, VoxelChunk / ChunkCoord3, topology records — composed from BCL primitives.

No dimension suffixes or 2D types in Math public APIs

• Forbidden: *3 / *2D suffixes on public Math types or members (Ray3, Sphere3, AxisAlignedBox3, …).
• Forbidden: System.Numerics.Vector2, Vector2D, or any Novolis 2D vector type.
• Planar XZ: System.Numerics.Vector3 with `Y = 0` (optional extension helpers on Vector3, not new vector types).

Owns:

• Pure spatial operations on BCL numerics
• Static helpers (e.g. Matrix4x4.CreateLookAt) that do not imply a clock, tick, or observer lifecycle

Hard rule — no time in Math:

If a concept needs time, deltaTime, clocks, ticks, integration steps, or “what happens next frame”, it does not belong in Math. That is Physics (physical evolution) or Simulation (orchestration and observation).

Does not own:

• Cameras (any rig, pose, or controller) → Simulation
• Forces, bodies, integrators → Physics
• Worlds, scenarios, replay → Simulation

`Novolis.Physics.*` — physical rules over time

Repo: novolis-physics

Depends on: Math only (Novolis.Math.* facets as needed).

Owns:

• RigidBody, MassProperties, Velocity, Acceleration
• Force, Torque, Material, Collider, Contact, Constraint
• Integrator, CollisionSolver, domain solvers (ballistics, orbits, gravity, aero)
• Stepping state forward with dt (physical time evolution)

Must not reference or know:

• Cameras, players, AI, networking, rendering, ECS, games
• Product occupancy conventions, maze generation
• Simulation-world tick ordering (orchestration is Simulation)

`Novolis.Simulation.*` — neutral runtime model

Repo: novolis-simulation

Depends on: Math, Physics only. Must not reference Novolis.Raylib.*, dogfooding, or SCR.

Owns:

• SimulationWorld, SimulationClock, SimulationStep
• ISimulationSystem, ISimulationState, ISimulationObject
• Snapshots, determinism policy, unit-system policy, tick ordering
• Scenario loading, recording / replay
• All cameras — rigs, poses, controllers, and composition:

StaticCameraRig, OrbitCameraRig, TrackingCameraRig, FreeLookCameraRig
FirstPersonCameraRig, ThirdPersonCameraRig, CharacterCameraDirector, CharacterMotor
LookIntent / MoveIntent, YawPitchController, ViewPose, ObserverFrame

• Tiles (Novolis.Simulation.Tiles) — Prison Architect–style layered maps, edge walls/doors, room flood-fill, grid A*
• Voxels (Novolis.Simulation.Voxels + .Meshing) — chunked block worlds, streaming, terrain fill, face-culled / greedy mesh → Math.Geometry (no GPU)

Primitive third-person, orbit, first-person yaw/pitch, and CAD-style viewport cameras belong here. Product-only embellishments (e.g. run bobbing, weapon recoil shake, cinematic beats tied to a specific game) stay in apps, not platform Simulation.

Humanoid skeleton / mocap target: Novolis.Simulation.Humanoid — Mixamo/Unity-compatible bone ids, T-pose bind, FK/IK (including two-bone and FABRIK chain), animation clips. Physics ragdoll bridge: Novolis.Simulation.Humanoid.Physics. Import: Novolis.Simulation.Humanoid.Import (BVH / glTF joints). CPU skin: Novolis.Simulation.Humanoid.Skinning. Game clip banks: Novolis.Game.Humanoid (gaming repo).

Kinematics vs skeletal IK (do not confuse)

Forbidden: IK solvers in Novolis.Math.*; putting TwoBoneIk / FABRIK into Simulation.Kinematics; treating joint constraint projection as IK.

Answers: How do multiple systems participate in one evolving world?

Naming: StarConflictsRevolt.Server.Simulation is product simulation. Novolis.Simulation.* is the platform library. Do not rename SCR projects.

Outside the stack

`novolis-rendering`

Separate repo and dependency island. Owns CPU framebuffer production (ray tracing, future software rasterizers). Does not open windows, call GPU APIs, or own platform cameras.

`novolis-raylib`

Separate repo and dependency island. Owns host loop, draw, input bindings, GPU types (e.g. Camera3D).

Raylib does not own platform camera logic; apps bridge observers to the renderer.

Apps (dogfooding, SCR, …)

Product rules, HUD, networking, highly specific camera feel (run bobbing, recoil). May reference Math, Physics, Simulation, and Raylib independently.

Placement guide

Package dependency graph

Spine (closed, low → high):

novolis-math          (Arrays, Geometry, Topology, core numerics)
novolis-physics       →  math
novolis-simulation    →  math, physics
  (facets: Abstractions, World, View, Tiles, Voxels, Voxels.Meshing, Kinematics, World.Builders, Racing, …)
novolis-gaming        →  math / physics / simulation as needed; never → Avalonia UI packages
novolis-avalonia      →  math…gaming + Avalonia.* ; never pull Avalonia into lower layers
apps / dogfood        →  compose freely (including Avalonia + Raylib + Simulation)

Orthogonal (not on the spine ranks; still Avalonia-free libraries):

novolis-machinelearning  (Core, Neural.*, AutoMl — building blocks only; no domain packages)

novolis-raylib       →  math only (if needed); never → simulation; never → Avalonia
novolis-rendering    →  math only; never → simulation or raylib; never → Avalonia

novolis-cad          →  Math only (Cad.Primitives, Cad.Blueprint, Cad.Evaluation, Cad.SceneBridge)
                         Avalonia-free .cadjson interchange + Cad→3D bridge
                         Must not host mesh scene graphs (those are Novolis.3D.*)
novolis-avalonia     →  also ships Avalonia-free Novolis.3D.Scene / Novolis.3D.Modeling / Novolis.3D.Import
                         (.nov3djson mesh graph; Modeling = Math.Geometry mesh-ops façade; Assimp import);
                         UI is Novolis.Avalonia.3D / Cad / Ship.Design

Cad vs 3D cameras: document pose bags (CadCamera, CameraNode) may live in Cad/3D DTOs. Orbit / free-look controllers and ViewPose stay in Novolis.Simulation.View. Apps/Avalonia compose DTO poses → ViewPose. Do not put Rendering soft-bridges in Cad libraries — apps wire Cad/3D lights → Rendering.

Apps may reference any combination; they own cross-repo glue.

Transitional state (2026-05)

Wave 7–11 migrations may still place types in legacy packages. Prefer the boundaries above for new code.

Related

• hexgame-authoritative-core.md — HexGame-shaped game loops: Tick in Simulation/apps; Physics is a callee only (no HexGame NuGet / no GameKit)
• workspace-snapshot-timeline.md — editor workspaces, save points, and branchable timelines (novolis-workspaces)
• gaming-layer-policy.md — novolis-gaming authoring lane (identity, menus, multiplayer glue, session protocol)
• simulation-layer-policy.md — operational summary
• wave-7-gameengine-math.md
• wave-11-simulation-repo.md
• local-nuget-development.md
• gameengine-reference-policy.md