OneCAD-Draft/INTEGRATION_GAPS.md

acadrust Integration Gaps

Missing or incomplete integrations between acadrust entity definitions and H7CAD rendering/interaction systems. Ordered by priority within each category.

Legend: ✅ Done · ⚠️ Partial · ❌ Not done

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Entity Field Gaps (acadrust fields ignored in tessellation)

High Impact

Status	Entity	Ignored Field(s)	Effect
✅	INSERT	column_count, row_count, column_spacing, row_spacing	MINSERT handled by acadrust::explode_from_document() → array_transforms()
✅	LWPolyline	constant_width, vertex start_width / end_width	Implemented in src/scene/mod.rs:3239
✅	Polyline (legacy)	Vertex2D.start_width / end_width	Implemented in src/scene/mod.rs

Medium Impact

Status	Entity	Ignored Field(s)	Effect
✅	Dimension	DIMSCALE, DIMASZ, DIMEXO, DIMEXE (from dimstyle)	Implemented in src/scene/tessellate.rs:263
✅	Spline	weights (rational NURBS control point weights)	NurbsCurve used when weights present — src/entities/spline.rs
✅	Spline	flags.closed / flags.periodic	Implemented in src/entities/spline.rs:48
✅	Hatch	BoundaryEdge::Spline tessellation	Implemented in src/scene/mod.rs:1802
✅	MultiLeader	MultiLeaderPathType::Spline	Implemented in src/entities/multileader.rs:76
✅	RasterImage	clip_boundary (polygonal/rectangular)	Implemented in src/entities/raster_image.rs — polygonal + rectangular clip

Low Impact

Status	Entity	Ignored Field(s)	Effect
✅	Arc / Circle / Line / LwPolyline / Polyline2D	thickness	Extrudes along WCS normal — src/entities/{arc,circle,line,lwpolyline,polyline}.rs
❌	LWPolyline	plinegen flag	Linetype pattern resets at each vertex instead of continuing

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Entity Type Gaps (entire types with missing subsystems)

Renders Nothing / Placeholder Only

Status	Entity	Notes
✅	Face3D	Full tessellation, grips, properties panel — src/entities/mesh.rs
✅	OLE2Frame	Bounding box + X mark with grips, properties panel, transform — src/entities/ole2frame.rs

Wire Fallback Only (no full mesh)

Status	Entity	Missing
⚠️	Solid3D / Region / Body	src/scene/solid3d_tess.rs exists with MeshModel support; no real mesh from ACIS data

Partial Render

Status	Entity	What works	What's missing
⚠️	Viewport (paper space)	Frame (active=gold, inactive=cyan), CPU projection + Cohen-Sutherland clipping, perspective, layer freeze per-viewport, MSPACE switching, pan/zoom/orbit	GPU scissor rect for pixel-level boundary clipping; stencil masking for overlapping viewports

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Systemic Gap — OCS→WCS Transform

✅ Done. The DXF arbitrary-axis algorithm is implemented in src/scene/transform.rs (ocs_axes, ocs_point_to_wcs). Applied to:

Status	Entity	Location
✅	Arc	src/entities/arc.rs
✅	Circle	src/entities/circle.rs
✅	Line	src/entities/line.rs
✅	Point	src/entities/point.rs
✅	Ellipse	src/entities/ellipse.rs
✅	LwPolyline	src/entities/lwpolyline.rs
✅	Spline	DXF spec: spline control points are already in WCS (normal field unused)
✅	Polyline2D	src/entities/polyline.rs — elevation + normal applied
✅	Polyline3D	Vertices already in WCS per DXF spec (no OCS transform needed)
✅	AttributeDefinition / AttributeEntity	OCS→WCS applied to insertion snap point — src/entities/attribute.rs
✅	Hatch	OCS→WCS applied to all boundary edge types — src/scene/tessellate.rs
✅	MLine / Leader	Vertices already in WCS per DXF spec; normal field unused for coord transform

Impact: Low for typical 2D plan files (nearly all normals are (0,0,1)); high for 3D DXF files with entities on non-horizontal planes.

The DXF arbitrary-axis algorithm (src/scene/transform.rs:73):

if |Wx| < 1/64 and |Wy| < 1/64:
    Ax = (0,1,0) × N
else:
    Ax = (1,0,0) × N
Ax = normalize(Ax)
Ay = N × Ax

Then transform each OCS point: WCS = x*Ax + y*Ay + z*N

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Render Style Gaps (color, linetype, lineweight resolution)

High Impact

Status	Gap	Effect	Location
✅	ByBlock color resolved through INSERT chain	Implemented via render_style_for_block_sub()	src/scene/render.rs:243
✅	ByBlock linetype resolved through INSERT chain	Implemented	src/scene/render.rs:260

Medium Impact

Status	Gap	Effect	Location
✅	ByBlock lineweight resolved from INSERT entity	Implemented	src/scene/render.rs:266

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Text & Style Gaps

Medium Impact

Status	Gap	Effect	Location
✅	TextStyle is_backward flag	Negative width_factor applied	src/entities/text.rs:60
✅	TextStyle is_upside_down flag	Rotation offset by π applied	src/entities/text.rs:63

Low-Medium Impact

Status	Gap	Effect	Location
✅	Complex linetype text shapes	LtSeg::Text calls cxf::tessellate_text_ex, LtSeg::Shape calls emit_shape — src/scene/complex_lt.rs

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Polyline3D Vertex Type Gap

✅ Done. src/entities/polyline.rs:305 — VertexFlags (SPLINE_VERTEX flag 8, SPLINE_CONTROL flag 16) properly detected and used for wire/snap point selection.

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Snap Point Gaps

Critical / High

Status	Entity	Missing Snap	Location
✅	INSERT	Insertion snap point	src/scene/mod.rs — appended after explode
✅	INSERT	Nested entity snap points	All sub-entity WireModels are flat-mapped into the scene wire list — snap sees them all
✅	Hatch	Snap points for circular arc boundaries	Center snaps added for CircularArc/EllipticArc edges — src/scene/tessellate.rs

Medium

Status	Entity	Missing Snap	Location
✅	Dimension	Node snap hints on defpoints	src/scene/tessellate.rs — dimension_snap_pts()
✅	Spline	Fit/control points in snap_pts	src/entities/spline.rs:38
✅	MultiLeader	Vertices and connection points in snap_pts	src/entities/multileader.rs
✅	MLine	Vertices in snap_pts	src/entities/mline.rs

Low

Status	Entity	Missing Snap	Location
⚠️	Ellipse (partial arc)	Endpoints not in pre-baked snap_pts	Arc endpoints emitted only as Center; functional via wire tessellation but semantically wrong
✅	Hatch	Elevation Z	Snap Z uses hatch.elevation - world_offset.z — src/scene/tessellate.rs:627

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Grip Gaps

Status	Entity	Missing Grip	Location
✅	LWPolyline	Midpoint grips for arc segments	src/entities/lwpolyline.rs:162

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Text Rendering Gaps

Status	Gap	Effect	Location
✅	TextStyle is_backward flag applied	Negative width_factor	src/entities/text.rs:61
✅	TextStyle is_upside_down flag applied	Rotation offset	src/entities/text.rs:64
⚠️	Unicode characters not in CXF fonts	Glyph lookup implemented; missing characters silently dropped without warning	src/scene/cxf.rs:74

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DXF Reader Unit Gaps (acadrust bugs we work around)

These are fixed in our post-load fix_dxf_dimension_rotations() in src/io/mod.rs.

Status	Entity	Field	DXF Code	Fix Location
✅	Dimension (Linear)	rotation	50	src/io/mod.rs:221
✅	Dimension (all)	text_rotation	53	src/scene/tessellate.rs::dimension_text_natural_rotation()
✅	AttributeEntity	rotation	50	src/io/mod.rs:224
✅	AttributeDefinition	rotation	50	src/io/mod.rs:219
✅	Shape	rotation	50	Fixed in fix_dxf_dimension_rotations() — src/io/mod.rs

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Coverage Summary

Subsystem	Coverage
Tessellation	34/41 entity types fully, 4 legacy fallback, 3 missing
Snap points	36/41 (Face3D, Solid3D, Region, Body, OLE2Frame missing)
Grip points	36/41 (same 5 missing)
Properties panel	36/41 (same 5 missing)
Hit testing	41/41 (all via fallback)

Gap Status Summary

Status	Count
✅ Done	46
⚠️ Partial	3
❌ Not done	0
Total	49

Remaining gaps by priority

Medium: Viewport GPU scissor rect (pixel-level boundary clipping for overlapping viewports)

Low: LWPolyline plinegen (GPU shader change needed)