ECAD > Working With ECAD Assemblies > Setting Up Board Design > About Boards in ECAD Assemblies
  
About Boards in ECAD Assemblies
In an ECAD assembly or subassembly, you create and edit a single board as a separate part. You can create a board with both rigid and nonrigid areas, referred to as rigid flex boards, or only rigid areas. After you create the board, you can assemble mechanical and electrical components relative to the top or bottom of the board surface.
Boards with only rigid areas can be modeled in MCAD or can be imported as a base EDMD file when the ECAD side begins the collaboration process. Boards with rigid and nonrigid areas are always modeled in MCAD. They must have a fixed geometry reference for the flat state.
When you create the board, a board CSYS overlapping the assembly CSYS is created automatically. When there is no assembly CSYS, the board CSYS is created at the absolute 0.0.0 with absolute direction and a coincident assembly CSYS. Best practice is to use a template for board parts that includes the model properties, parameters, and other frequently used settings.
The first board segment is automatically defined as the fixed geometry reference of the board. When you create the first board segment, the board datums are automatically created and placed in a group. These default datums are used when you export the ECAD assembly or subassembly as a base EDMD (*.idx) file (or as a base ECAD EDA (*.eda) file) and for ECAD-MCAD collaboration.