Constructive solid geometry

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Constructive solid geometry (CSG) is a modelling paradigm that is used in many traditional CAD systems. It essentially consists of using primitive solid objects and doing boolean operations with them, such as fusion, subtraction and intersection, in order to create a final shape.

In FreeCAD, this method is mostly utilized with the Workbench Part.svg Part Workbench, which has the ability of creating primitive objects like Part Box.svg boxes, Part Cylinder.svg cylinders, and Part Sphere.svg spheres and fuse them together, or use them to cut other objects with tools like Part Cut.svg Part Cut.

Part Constructive Solid Geometry workflow.svg

Constructive solid geometry (CSG) workflow; any number of operations can be done on solid primitives to create other solid objects, and then fuse or cut them until the final shape is produced.

Alternatively, the Workbench PartDesign.svg PartDesign Workbench uses a more modern approach than simple CSG; this method is called feature editing, which means creating a base solid, and then adding sequential parametric transformations to obtain a final body.

Note: A PartDesign Body created with the PartDesign Workbench can also be used in a boolean operation with other objects.


Part CGS workflow example.svg

Example of constructive solid geometry (CSG) workflow: primitive parts are fused (union); the intersection of two other primitive parts is calculated (common); the difference (cut) of the two previous shapes is obtained.


The tutorials page provides some examples on creating solids with the Workbench Part.svg Part Workbench that use the CSG method.