Toward Optimistic Version Control in Architecture

Diffing, Patching, and Three-Way Merging for openNURBS 3D Models

Appendix B

OpenNURBS Geometry Types

This appendix outlines the breadth of geometric constructs supported by the openNURBS file format by enumerating the subclasses of ON_Geometry.

ON_Annotation: extends ON_Geometry; The base class for annotation objects.
ON_ArcCurve: extends ON_Curve; An arc or circle.
ON_Brep: extends ON_Geometry; A boundary representation, or B-rep. In computer graphics, boundary representations are a method of defining three-dimensional shapes in terms of the surfaces that enclose them.
ON_BrepEdge: extends ON_CurveProxy; An edge between two faces in a B-rep.
ON_BrepFace: extends ON_SurfaceProxy; A face in a B-rep.
ON_BrepLoop: extends ON_Geometry; The set of curves that define the edges of a single face in a B-rep.
ON_BrepTrim: extends ON_CurveProxy; A curve that trims a face in a B-rep.
ON_Centermark: extends ON_Dimension; An annotation that marks the center of a circle or arc.
ON_ClippingPlaneSurface: extends ON_PlaneSurface; A planar surface that is used as a clipping plane in one or more viewports.
ON_Curve: extends ON_Geometry; The base class for curves. In openNURBS, all one-dimensional geometric objects are considered to be curves even if they do not "curve" in the conventional sense.
ON_CurveOnSurface: extends ON_Curve; A curve that lies on a surface.
ON_CurveProxy: extends ON_Curve; A curve-like structure that is stored as part of another type of geometry. Proxy objects are not saved in an openNURBS file and only exist at runtime.
ON_DetailView: extends ON_Geometry; A viewport bounded by a closed planar curve.
ON_DimAngular: extends ON_Dimension; An annotation that shows the angle between two curves or surfaces.
ON_Dimension: extends ON_Annotation; The base class for dimension annotations.
ON_DimLinear: extends ON_Dimension; An annotation that shows the distance between two points.
ON_DimOrdinate: extends ON_Dimension; An annotation that shows the distance from the model's origin point.
ON_DimRadial: extends ON_Dimension; An annotation that shows the radius or diameter of a circle or arc.
ON_Extrusion: extends ON_Surface; A surface created by extruding a curve along a linear path.
ON_Hatch: extends ON_Geometry; A planar region filled with a hatch pattern.
ON_HLDCurve: extends ON_CurveProxy; A curve that is the result of projecting a three-dimensional object into a two-dimensional hidden line drawing.
ON_InstanceRef: extends ON_Geometry; A copy of an \texttt{ON_InstanceDefinition
ON_Leader: extends ON_Annotation; A line that points from an annotation toward the model entity it describes.
ON_Light: extends ON_Geometry; A source of light used when rendering a model.
ON_LineCurve: extends ON_Curve; A straight line between two points.
ON_Mesh: extends ON_Geometry; A polygonal mesh. In computer graphics, meshes are a method of approximating a complex shapes through a network of planar, polygonal surfaces.
ON_MeshComponentRef: extends ON_Geometry; A face, edge, or vertex within a mesh.
ON_MorphControl: extends ON_Geometry; An object that controls the morphing behavior of another object.
ON_NurbsCage: extends ON_Geometry; A network of control points that defines the shape of a NURBS surface.
ON_NurbsCurve: extends ON_Curve; A non-uniform rational basis spline (NURBS) curve. All other types of curve are representable as and can be converted to a NURBS curve.
ON_NurbsSurface: extends ON_Surface; A non-uniform rational basis spline (NURBS) surface. All other types of surface are representable as and can be converted to a NURBS surface.
ON_OffsetSurface: extends ON_Surface; A surface that is offset from another according to some algorithm.
ON_PlaneSurface: extends ON_Surface; A planar surface.
ON_Point: extends ON_Geometry; A point in three-dimensional space.
ON_PointCloud: extends ON_Geometry; A collection of points such as those acquired by a 3D scanner.
ON_PointGrid: extends ON_Geometry; A set of regularly-spaced points.
ON_PolyCurve: extends ON_Curve; A curve that consists of other, simpler curves laid end-to-end.
ON_PolyEdgeCurve: extends ON_PolyCurve; A multi-part edge of a face in a B-rep.
ON_PolyEdgeSegment: extends ON_CurveProxy; A piece of a ON_PolyEdgeCurve.
ON_PolylineCurve: extends ON_Curve; A curve that consists of one or more linear segments.
ON_RevSurface: extends ON_Surface; A surface created by rotating a curve about an axis.
ON_SubD: extends ON_Geometry; A subdivision surface. In computer graphics, subdivision surfaces are a method of defining complex shapes through a network of control points and a set of algorithms that interpolate the surfaces between those control points.
ON_SubDComponentRef: extends ON_Geometry; A face, edge, or vertex within a subdivision surface.
ON_SumSurface: extends ON_Surface; A surface created by extruding a curve along a curved path.
ON_Surface: extends ON_Geometry; The base class for surfaces.
ON_SurfaceProxy: extends ON_Surface; A surface-like structure that is stored as part of another type of geometry. Proxy objects are not saved in an openNURBS file and only exist at runtime.
ON_Text: extends ON_Annotation; A textual annotation.
ON_TextContent: extends ON_Geometry; A textual label that is part of an annotation component.
ON_TextDot: extends ON_Geometry; A small textual label that keeps itself aligned with the viewing plane so it is always legible.
ON_Viewport: extends ON_Geometry; The field of view of a virtual camera.

Toward Optimistic Version Control in Architecture

Appendix B OpenNURBS Geometry Types

Appendix B

OpenNURBS Geometry Types