Component

A component is the structure SketchUp and many other 3D programs use for repeated objects. The geometry is defined once, and every copy placed in the model is an instance of that definition. Open one of twenty windows, change its frame, and the other nineteen change at the same moment.

Why components help

The first gain is time: fixing a repeated element in one place is far safer than hunting through the whole project. The second is file size; because the geometry is stored once, hundreds of chairs or trees take up little space. Render engines usually handle component instances through instancing, which keeps memory use down. In SketchUp a component can be set to glue to a surface and cut its own opening in a wall, which is very handy for windows and doors.

Component or group?

A simple rule works well: if the same part appears two or more times, make it a component; if it is a one-off, make it a group. When one copy needs to differ from the rest, that instance can be made unique and detached from the definition. Clear names make it easier to assign materials, take off quantities and organize the render scene later. Hundreds of unnamed components, on the other hand, turn into an impossible list in a large model. Our guide to using SketchUp in architecture shares more habits that keep models tidy.