Cic_3089.ENU.bmp Union

(a) Original objects
and (b) the objects unioned.
They look the same but the latter
is all a single volume.
The Union tool options palette.

This tool merges two intersecting objects together. If the objects do not overlap, the result is the objects themselves. In its simplest manifestation it involves two objects. To apply it, with the tool active, click on the two objects. The result appears immediately and the original objects are ghosted.


When the objects that are unioned contain coplanar faces, the resulting object also contains coplanar faces the edges between which may be kept or filtered out. This depends on whether the Keep Edges in the Union tool options palette is on or off.


It is sometimes required to union many objects. While such unions can be executed one at a time, by sequentially picking pairs of objects, they can also be executed all in one step. The objects can be prepicked using either an area pick method, or by picking them individually with the Pick tool while pressing shift and then, with the Union tool clicking anywhere in the project window. Or the postpick method can be used by multi-picking the objects sequentially with the Union tool, while pressing shift, then releasing shift and clicking anywhere in the project window. See example.

Union Example 1
(a) Original objects and (b) the unioned object.