cplanes

A cplane, short for construction plane, is a fundamental concept in many computer-aided design (CAD) and 3D modeling software applications. It acts as a user-defined reference surface or plane upon which 2D geometry is drawn or 3D objects are created and manipulated. Think of it as a temporary, movable drawing board within the 3D environment.

The default cplane is typically aligned with one of the primary axes, such as the XY, YZ, or XZ planes. However, users can easily reposition, rotate, and orient the cplane to suit their modeling needs. This flexibility allows for drawing and extruding features at any angle or on any surface within the 3D model. For example, one might align a cplane to a curved surface to sketch a new profile that will then be swept along a path.

Manipulating the cplane is a core skill for efficient 3D modeling. It simplifies the process of creating complex geometry by allowing users to work directly on the desired plane without needing to constantly adjust their viewpoint or rely on complex coordinate system transformations. Many software packages offer various tools for creating and managing cplanes, including snapping to existing geometry, using explicit coordinates, or selecting faces of existing objects. The ability to save and recall specific cplane configurations is also a common feature.