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Class Definition: solid.Shape

drafting: solid.Shape

A solid in millimetres, modelled through Open CASCADE.

solid.Shape holds the exact boundary of one or more solids: every face a plane, cylinder, cone, sphere, torus or spline surface, every edge a line, circle or curve, with nothing approximated by facets. It is what the functions of the solid namespace create, what the boolean operators combine, and what its write method saves as STEP for exchange or STL for printing.

Primitives are made by

  • solid.box
  • solid.cylinder
  • solid.cone
  • solid.sphere
  • solid.ellipsoid
  • solid.torus
  • solid.wedge

and solids from +geom objects by

  • solid.extrude
  • solid.revolve
  • solid.loft
  • solid.sweep
  • solid.helix

A solid is made from a closed triangle mesh by solid.polyhedron, and from a grid of points by solid.surface, which fits a surface through the grid and thickens it. hull wraps shapes and points in their convex hull, and solid.read loads solids from a STEP file.

Finally, shapes can be combined by the three boolean CAD operations, each taking any number of shapes:

MethodResult
unionthe material of any of them
subtractthe material of the first that is in none of the others
intersectthe material common to all of them

Features are worked on a shape by methods: hole drills plain, counterbored, countersunk and tapping holes, pocket cuts a region into it, fillet and chamfer round or bevel edges, and shell hollows the shape. The edges and faces they act on are chosen by edges and faces, by the kind of curve or surface, by direction and by position. section cuts a shape with a plane into regions, which the solid functions build from again, and projection gives the outline of a shape seen along a direction as regions in the same way.

The class is a value class. Every operation returns a new shape and leaves its operands unchanged, and a copy is independent of the original. The empty shape adds nothing to a union and empties an intersection, and a boolean whose result holds no material, such as the intersection of two solids that do not meet, returns it. A shape is saved and loaded with save and load like any other value.

See also: solid.box, solid.read, solid.Shape.write, solid.Shape.show

Source Code: solid.Shape

The solid.Shape class contains the following properties:

An N-by-3 matrix of red, green and blue from 0 to 1, a row for each of the shape’s N solids in the order solid.Shape.numsolids counts them, a row of NaN for a solid without a colour, or empty when none has one. Assigning a single row colours every solid. The viewer shows it, and a STEP file carries it out and in. A transform keeps it, and each solid a boolean or a feature makes takes the colour of the first coloured solid it came from, so parts apart keep their own; the tools of subtract give none.

The solid.Shape class offers the following public methods:

Shape Make a shape.
union The union of shapes, the material of any of them.
subtract The difference of shapes, the material of the first in none of the others.
intersect The intersection of shapes, the material common to all of them.
tessellate A triangle mesh of a shape.
show Show a shape in a viewer of its own, redrawing in place.
write Write a solid to a STEP, STL, OBJ, PLY or 3MF file.
translate Move a shape by the vector V.
rotate Rotate a shape about an axis.
mirror Reflect a shape in a plane.
scale Scale a shape uniformly about a point.
volume The volume of a shape in cubic millimetres.
area The surface area of a shape in square millimetres.
centroid The centre of volume of a shape, as a 1-by-3 vector in millimetres.
bbox Axis-aligned extents of a shape.
isvalid True if a shape passes Open CASCADE's validity check.
isempty True for the empty shape, which holds no material.
numsolids The number of separate solids in a shape.
numfaces The number of faces of a shape.
numedges The number of edges of a shape, each counted once.
edges Choose edges of a shape, to round, chamfer or inspect.
faces Choose faces of a shape, to open when hollowing it or to inspect.
fillet Round edges of a shape to a radius.
chamfer Bevel edges of a shape.
shell Hollow a shape to a uniform wall thickness.
hole Drill holes into a shape.
pocket Cut a pocket into a shape.
section Cut a shape with a plane.
projection Outline of a shape seen along a direction.
hull The convex hull of shapes and points.
resize Scale a shape to a size.
copy Copies of a shape, united.
rectarray Copies of a shape in rows, columns and layers, united.
polararray Copies of a shape round an axis, united.