Groups

Brush groups allow you to select a bunch of geometry and/or entities and group them into a named collection which you can then hide or select. This allows you to work with greater speed in a number of ways.

First, you can group large areas of geometry together and hide it in order to unclutter the views. When a level becomes complex, there is frequently a large amount of excess geometry in the views that you are not interested in at any particular point in time. Hiding parts of the level like this allows you to more easily select and manipulate the geometry that you are most interested in.

Geometry which is grouped and hidden is not included when displaying the level in the textured view, which can dramatically improve the editor's performance when dealing with complex levels.

Geometry which is grouped and hidden is not used when compiling the level, which means that the time required to compile the level can be greatly reduced by hiding large parts of the level. This becomes very important when you're texturing and lighting a level because you'll be making many small changes and recompiling frequently. Building a level with lighting--especially radiosity lighting--takes a long time.

This is where brush groups can help. Since you're typically lighting a single room at a time, you can group and hide all but the room on which you're working. Then, when you build the level only that room will be compiled. This will take much less time than rebuilding the entire level. You will still have to do a full radiosity build with all groups visible periodically to work on portions of the level that require light blending between rooms, and for the final level, but you should be able to save a considerable amount time by working on a single room at a time.

In addition to the Groups option page, on which you can control individual groups' visibility, three toolbar buttons allow you to control which groups are displayed by the editor and used when compiling the level. If the All Groups button is selected, then all groups are displayed, regardless of their individual visibily attributes. If the Visible Groups button is selected, then only those groups that have their individual visibility flags set will be displayed. If the Current Group button is selected, then only the currently-selected group is displayed.