Module build 

Building topology from geometry.

One level above Model’s raw builders: these take geometry, derive the topology it implies, check the invariants that need geometry to check, and report history.

What “checked” means here

Model::add_wire verifies that its children are edges. That is all it can do, because it has no geometry. make_wire additionally verifies that consecutive edges actually meet, which is the property that makes a wire a connected path rather than a bag of edges, and which every algorithm downstream assumes without checking. A wire whose edges do not join produces a face with a gap in its boundary, and the first thing to notice is usually a boolean, several operations later.

Modules

roles

Roles a builder assigns, so a rebuild can match entities up.

Functions

attach_pcurve

Attach a pcurve to an edge, describing it in a surface’s parameter space.

attach_seam

Attach a seam representation to an edge: one pcurve per side of a closed surface’s join.

belted_wire

The one wire a face on a B-spline closed round in u takes when its file bounds it by rings alone and writes no seam: each ring runs the whole period along the chart, from one end column to the other, and without a seam no ring meets another, so the boundary encloses nothing in the chart. The seam is the surface’s own column at the period’s join, exact (the iso-curve the control columns trace), from where one ring’s walk ends to where the next begins; walked up one end column and back down the other, it closes the two rings into one loop. A single ring opposite a row the surface collapses to a point (a dome’s pole) takes the seam to that point and back, and the pole’s run across the chart is laid by closed_at_poles.

chain_wire_branches

Put a face’s wires on one branch of a periodic chart.

closed_at_poles

A wire’s edge uses with the chart closed where the surface collapses.

covers_whole_surface

Whether a face covers the whole of its surface: it has a wire, and every edge its wires walk has no length or is a seam of that surface walked once each way.

edge_vertices

The vertices an edge runs between, in the direction it is traversed.

edges_turn

How a closed walk of edge occurrences turns about axis: twice the area it encloses projected square to the axis, signed by the right-hand rule, from points sampled along the edges in traversal order. Positive for a ring walked counter-clockwise about axis.

find_plane

The plane a shape lies in, if it lies in one.

is_shell_closed

Whether every edge in a shell is shared by exactly two faces.

is_wire_closed

Whether a wire’s last edge returns to its first edge’s start.

make_apex_band

Build the face of a revolution cap: one closed ring belting a cone, with the apex the file never wrote synthesised as the degenerate ring the band needs.

make_band_between

Build the face of a band between two closed rings that need not be circles, each with a caller-supplied chart image.

make_band_of_rings

Build the face of a band between two closed rings of edges on a periodic analytic surface, joined by a synthesised seam.

make_compound

Build a compound from any shapes, with history.

make_compsolid

Build a shell from faces.

make_edge

Build an edge on curve, bounded by its own endpoints.

make_edge_between

Build an edge between two existing vertices, on curve.

make_face

Build a face on surface, bounded by wires.

make_face_on

Build a face on a surface the model already holds.

make_face_with_pcurves

Build a face on surface from per-wire edge lists, attaching an exact same-parameter pcurve to every edge.

make_natural_face

Build a face covering the whole of surface, with no trimming.

make_polygon

Build a wire of straight segments through a sequence of points.

make_profile_revolution_band

make_revolution_band on a curve revolved a whole turn about an axis (RevolutionSurface), its rings the parallels through the profile’s two ends.

make_revolution_band

Build the face of a revolution band: two closed rings joined by a synthesised seam, pcurves attached window-coherently.

make_shell

Build a shell from faces.

make_solid

Build a solid from shells.

make_vertex

Add a vertex at point.

make_wire

Build a wire from edges that meet end to end.

placed_edge_curve

An edge occurrence’s curve where the occurrence stands, and the range of it the edge covers; None for an edge with no curve in space.

rings_are_parallels

Whether two closed ring edges are parallels of surface, so that make_revolution_band can build a band between them. A reader asks this first: a periodic face bounded by two closed circles that are not parallels (a button head’s rims, square to the screw on a sphere whose chart runs along z) is a legitimate face on its own bounds, not a band missing its seam, and deserves no warning.

split_ring_on_column

Split a closed circle rim of a revolution band where it crosses the column of anchor, the vertex of the band’s other rim, so both rims have a vertex on one column and a seam can join them.

surface_iso_u_curve

The surface’s u = at iso-curve, parameterized by v exactly.

trimmed_or_fitted_where_bare

As trimmed_where_bare, with every edge left without a closed form given a pcurve fitted by projection at the curve’s own parameters: a face kept whole in a solid (a sweep’s end) is only valid with a trim on every edge.

trimmed_where_bare

Give every edge of face that has no trim on the face’s surface its exact one, where a closed form exists: a profile built from bare curves becomes a face a sweep can keep as an end.