Basic NMG structural hierarchy definitions, including the necessary geometric definitions. More...

Collaboration diagram for Topology:

Files
file	topology.h

Data Structures
struct	vertex
	NMG topological vertex - the simplest element of the topology system. More...

struct	vertexuse
	NMG topological vertex usage. More...

struct	edge
	NMG topological edge. More...

struct	edgeuse
	NMG topological edge usage. More...

struct	loop
	NMG topological loop. More...

struct	loopuse
	NMG topological loop usage. More...

struct	face
	NMG topological face. More...

struct	faceuse
	NMG topological face usage. More...

struct	shell
	NMG topological shell. More...

struct	nmgregion
	NMG topological region. More...

struct	model
	NMG topological model. More...

struct	vertex_g
	Point in 3D space. More...

struct	edge_g_lseg
	Line in 3D space. More...

struct	face_g_plane
	Planar face geometry. More...

struct	knot_vector
	Definition of a knot vector. More...

struct	edge_g_cnurb
	Edge NURBS curve geometry. More...

struct	face_g_snurb
	Face NURBS surface geometry. More...

struct	vertexuse_a_plane
	Vertexuse normal. More...

struct	vertexuse_a_cnurb
	Vertexuse NURBS parameters. More...

struct	loop_a
	Loop bounding box. More...

struct	shell_a
	Shell bounding box. More...

struct	nmgregion_a
	Region bounding box. More...

Detailed Description

Basic NMG structural hierarchy definitions, including the necessary geometric definitions.

This is the interconnected hierarchical data scheme proposed by Weiler and documented by Muuss and Butler in: Combinatorial Solid Geometry, Boundary Representations, and Non-Manifold Geometry, State of the Art in Computer Graphics: Visualization and Modeling D. F. Rogers, R. A. Earnshaw editors, Springer-Verlag, New York, 1991, pages 185-223: https://ftp.arl.army.mil/~mike/papers/90nmg/joined.html

Because of the interconnectedness of these containers, they are defined together rather than in separate headers - all of the "use" containers need to know about other use container types, as seen in Figure 4 from the Muuss/Butler paper:

Model
  |
Region
  |
Shell
||||
|||*--> Faceuse <--------> Face
|||          |
||*---> Loopuse <--------> Loop
||      |    |
|*------|--> Edgeuse <---> Edge
|       |    |
|       *--> Vertexuse <-> Vertex
*------------^

Each element has a direct connection to its parent and child types. The elements are defined thusly:

Vertex: a unique topological point
Edge: a line or curve terminated by one or two Vertices
Loop: a single Vertex, or a circuit of one or more Edges
Face: one or more Loops defining a surface. Exterior Loops include an area, interior Loops exclude an area
Shell: a single Vertex, or a collection of Faces, Loops and Edgesa
Region: a collection of shells
Model: a collection of regions

The "use" notation refers to a conceptual separation between an entity and a reference to that entity. For example, a face has two sides - each of those sides is individually referenced by a "use" of the underlying face data structure, with the faceuse adding additional information to identify the specific side associated with that particular application of the underlying face data.

Files

Data Structures

Detailed Description