SceneLab mesh modeller (wireframe + poly edit)

name: SceneLab mesh modeller overview: Turn SceneLab into a C4D-inspired mesh modeller by expanding Novolis.Avalonia.3D with many reusable editor controls, adding component-level (point/edge/polygon) wireframe editing on EditableMesh, and growing the Cinema4D-style primitive set — without starting a second dogfood app. todos:

• id: edit-state

content: Add SceneEditMode + MeshEditState; Make Editable bake; session seteditmode/selectcomponents/moveselection status: completed

• id: viewport-pick

content: Wireframe display modes, component highlight, ray pick, translate gizmo in SceneViewportRenderer/Control status: completed

• id: avalonia-controls

content: Ship SceneEditModeBar, PrimitivePalette, MeshEditToolStrip, MeshAttributePanel, TransformHud, ModifierStackPanel, DisplayModeBar; SceneLab composes them status: completed

• id: primitives

content: Add Pyramid, Disc, Tube, Platonic, Landscape to MeshPrimitiveKind + PrimitiveMesher + UI/schema status: completed

• id: mesh-ops

content: Selection-aware Extrude/Inset/Bevel/Bridge/Dissolve/Knife on EditableMesh status: completed

• id: verify-dogfood

content: Samples + unit tests; SceneLab ProjectRef run; package publish path status: completed isProject: false

Decision

Deepen [SceneLab](novolis-dogfooding/apps/avalonia/SceneLab) and grow [Novolis.Avalonia.3D](novolis-avalonia/src/Novolis.Avalonia.3D) into a component library. Do not add a parallel MeshLab app. Stay on .nov3djson / Modeling.Scene — not Cad/.cadjson.

Today SceneLab is Object Manager + procedural stack + whole-mesh wireframe with node-only selection. The gap for “C4D wireframe + mesh editing” is component selection in the viewport plus selection-aware tools and real Avalonia chrome.

flowchart LR
  subgraph ui [Avalonia.3D controls]
    ModeBar[SceneEditModeBar]
    PrimPal[PrimitivePalette]
    MeshTools[MeshEditToolStrip]
    OM[ObjectManagerControl]
    VP[SceneViewportControl]
    Attr[MeshAttributePanel]
    Props[PropertyInspectorControl]
  end
  subgraph core [Modeling.Scene]
    Doc[SceneDocument]
    Edit[MeshEditState]
    Eval[SceneEvaluator]
  end
  ModeBar --> Edit
  MeshTools --> Session
  VP -->|pick/drag| Session
  Session[SceneSessionService] --> Doc
  Session --> Edit
  Eval --> VP

Phase 1 — Edit model + wireframe viewport

Selection / edit state in Modeling.Scene (next to document, not only UI):

• SceneEditMode: Object | Point | Edge | Polygon
• MeshEditState: selected vertex/edge/face indices for the active MeshNode; soft-radius later
• Persist editable topology on mesh objects: when entering Point/Edge/Polygon on a procedural mesh, bake eval result into MeshNode vertices/indices (make Current State), then ops mutate that mesh — matches C4D “Make Editable”

Viewport (`SceneViewportRenderer`, `SceneViewportControl`):

• Display modes: Wireframe (default), Wire + points, Isoline (edges + optional face tint for selection)
• Draw selected points as markers, selected edges thicker/cyan, selected faces hatch/tint
• Ray pick: closest vertex / edge / triangle under cursor (camera ray vs mesh in world space); click selects; Shift multi-select
• LMB: pick when not on gizmo; MMB/Alt+LMB: orbit (keep current orbit); scroll zoom
• Simple move gizmo (axis lines) for selected components — translate only in v1

Session actions: seteditmode, selectcomponents, moveselection, makeeditable, plus existing object ops.

Phase 2 — Avalonia component library (lots of controls)

Refactor `SceneEditorSurface` toward CAD-style factory: build chrome, let SceneLab dock (like DraftStudio). Keep a default self-composed layout for the sample.

New reusable controls under Novolis.Avalonia.3D/Ui/:

Upgrade existing: editable numeric fields in PropertyInspectorControl; richer ObjectManagerControl icons by node kind.

SceneLab MainWindow composes these into a C4D-ish layout: top mode + primitives + mesh tools; OM | viewport | attributes+properties; bottom status.

Phase 3 — Cinema4D-style primitives

Extend `MeshPrimitiveKind` + `PrimitiveMesher`:

Add: Pyramid, Disc, Tube (hollow cylinder), Platonic (Tetra/Octa/Icosa/Dodeca), Landscape (heightgrid plane).

Keep existing: Box, Sphere, Cylinder, Cone, Plane, Capsule, Torus.

Params on MeshNode (segments, fillet/radius where relevant) editable via PrimitivePalette + property panel. Schema + session addmesh updated.

Phase 4 — Selection-aware mesh tools

Move shaping from whole-mesh stubs to ops on selection using `EditableMesh` + existing kernels:

• Extrude selected faces (offset along normals, create side walls)
• Inset selected faces
• Bevel selected edges (real edge bevel, replace AABB hack)
• Bridge two equal edge loops (wire up `MeshBridge`)
• Dissolve edges / faces
• Knife (plane cut via `MeshPlaneSplit` on selection or whole mesh)
• Keep Weld / Optimize / Subdiv as object or selection-scoped

Object mode still applies generators (Array/Boole/Symmetry) as today.

Phase 5 — Dogfood, tests, packages

• SceneLab samples: edit-box (make editable + extruded faces), prim-gallery (all primitives), existing cloner/boole kept
• Unit tests: pick math, make-editable bake, face extrude, component selection DTOs
• Explicit Raylib PackageReferences already on dogfood SceneLab — keep ProjectRef working
• Publish Avalonia/Modeling packages via normal GPR path after merge (no local feeds)

Out of scope

Animation, MoGraph fields, sculpt brushes, UVs, shaded PBR materials, Cad solid boolean merge, trademarked Cinema4D UI cloning (Object Manager / Modeling / Look naming only).