DesignBuilder provides some very powerful modelling tools for combining blocks in various ways to create new more complex geometric forms. Boolean geometry (otherwise know as Constructive solid geometry or CSG) provides these functions:
The union operation can be applied to any block including building blocks, component blocks and outlines blocks, whereas the difference and intersection methods only apply to outline blocks. This is because the outline block is the only block type that allow the block intersections required for these operations. Outline blocks resulting from the boolean operation can then be converted to building or component blocks.
The first step in using the boolean operations is to go to building level and select the 2 blocks to which the command is to apply.
The 2 blocks to be combined are shown above before the operation is started- a 3.5m height L-shaped block and a tall sports hall block.
When the 2 blocks are both selected the screen looks as above with the Boolean operations toolbar icon enabled.
Pressing on the toolbar icon at this stage starts the command and the Display options panel is displayed in the bottom left of the screen. On this panel there is a drop list with the 3 boolean functions available for selection. In the case where 2 building blocks are selected, only the Union operation is allowed. This is because building blocks cannot intersect and the difference and intersection options require intersection to work.
Once the command has been started the 2 blocks will become purple. To complete the operation, click on the edit screen with the mouse.
After the final click, the 2 blocks are merged into a single block (above).
This can be a very useful way to simplify geometry avoiding use of interconnecting blocks and the associated block connection surfaces, reducing the number of surfaces and easing the creation of zones that may span what were multiple blocks.
Note: the first implementation of DesignBuilder boolean geometry has some limitations when used with building blocks. You will find that with some building block geometries, a union operation is not possible. Also some more complex outline block geometries created using boolean geometry cannot be converted to building blocks. These limitations do not apply when working directly with component blocks or when converting outline blocks to component blocks.