Novolis Docs
novolis-modeling / design.md

Modeling design

Renderer-neutral modeling domain

dotnetgeometryassetsnovolis

Layer placement

novolis-modeling is an Avalonia-free orthogonal library island. It may depend on Novolis.Math.Geometry and third-party asset-format libraries. It must not depend on Avalonia, rendering, Raylib, simulation, CAD, or application hosts.

flowchart LR
  math[Novolis.Math.Geometry]
  scene[Novolis.Modeling.Scene]
  import[Novolis.Modeling.Import.Assimp]
  cad[Novolis.Cad.SceneBridge]
  ui[Novolis.Avalonia.Modeling]
  app[Application host]

  scene --> math
  import --> math
  cad --> scene
  ui --> scene
  ui --> import
  app --> ui
  app --> cad

Package responsibilities

Novolis.Modeling.Scene

Owns the renderer-neutral scene document, hierarchy, transforms, mesh instances, materials, lights, cameras, staged evaluation, editing state, and .nov3djson serialization. Evaluation produces Novolis.Math.Geometry values; it does not create GPU or renderer objects.

Novolis.Modeling.Import.Assimp

Owns translation from Assimp-supported external assets into Geometry meshes and Modeling-compatible skin data. It contains no UI or renderer policy.

Geometry ownership

Mesh storage and algorithms remain in Novolis.Math.Geometry: booleans, welding, splitting, topology, primitive tessellation, and geometric picking. Modeling composes those operations into a scene; it does not create a duplicate mesh-algorithm façade.

Novolis.Modeling.Scene owns the evaluated mesh boundary. EvaluatedMesh retains the existing position/index/world contract and adds optional normals, tangents, UVs, material slots, curvature, cavity, topology, adjacency, bounds, LOD, quality, readiness, and deterministic metadata. MeshAttributeGenerator provides deterministic CPU normal, tangent, UV, curvature, and cavity passes; the generated values remain renderer-neutral.

MeshQualityProfile controls which optional values are generated and whether topology/adjacency and a deterministic LOD reduction are requested. MeshEvaluationMetadata separates geometry hashes from full semantic hashes and includes the contract, mesher, modifier, quality, LOD, and attribute inputs in the cache identity. Local geometry hashes intentionally exclude source IDs and world placement.

Readiness is split into geometry and appearance stages. A mesh can be geometry-ready while an intentionally reduced quality profile omits normals or UVs. MeshContractValidator derives available attributes from actual arrays and topology, so appearance-only operations cannot report omitted geometry or silently claim a geometry change.

Document authority

Generic 3D products may author and persist SceneDocument. CAD and ship products author CadDocument and derive a SceneDocument through Novolis.Cad.SceneBridge. The CAD projection is one-way in this boundary; scene-to-CAD round-tripping is not implied.

Renderer conversion belongs to a renderer-owned adapter or an application composition root. The scene package must not contain renderer-shaped DTOs.