Basics

Example A toy plane from sketches on planes in 3D A brake disc: one hole, 24 copies A coating offset from an airfoil spline

planex2d has a small set of geometry objects, each with clearly defined properties. Edges can be lines, circular arcs or full circles, or splines. Lines and circular edges use exact geometry.

A wire is one chain of edges, open or closed, that does not cross, overlap or branch. A figure eight, for example, consists of two wires, and so does a T. A face is one region bounded by an outer loop and any holes, with no overlapping regions, free edges or zero-length edges. A shape groups faces and wires that have been cut against each other, and faces that meet share their edges. A compound is a simple collection of objects.

Every wire, face and shape lies in a plane that can be positioned anywhere in 3D. Names, colors and mesh sizes travel with the geometry through Boolean operations and export. Geometry has no built-in unit. Lines and arcs are exact, and rounding matters only where two independent computations have to agree. See Objects in planex2d for an overview of the geometry model.

In this section

Objects

Objects in planex2dThe geometry objects, their guarantees and how to construct them.

Lines and arcsLines, circular arcs and full circles, with shared vertices and edge data.

SplinesSmooth curves in Boolean operations and offsets, from airfoils to cams.

Wires and facesBuilding wires and faces from edges, with holes determined by nesting.

Faces, shapes and compoundsBoolean results, regions built from wires and faces that share edges.

In space

The plane in 3DWorking on any plane, including a solid face or another object's plane.

Moving, rotating, mirroring, scalingTransformations, symmetry and patterns, from a T-slot nut to a brake disc.

Data

Names and colorsNames, colors and mesh sizes on edges, faces and vertices, including their behaviour in Boolean operations.

UnitsGeometry has no built-in unit; learn how to interpret lengths and imported files.

TolerancesWhere geometric calculations are exact and where floating-point rounding matters.

3D

Pad and PocketSolids from faces and sketches, extruded and cut with OpenCASCADE, named after the profile.