Use assembly settings to control the behavior of assembly-related commands.
Work with assembly settings the same way you work with other object settings in AutoCAD Civil 3D, using the Toolspace Settings tree. You can control assembly-related settings at both the object collection (feature) level and at the command level.
Right-click the Settings tree Assemblies collection to establish defaults for all assembly-specific settings and to override the drawing ambient settings for all assembly-related commands. Use the Commands collection in the Settings tree Assembly collection to override assembly-specific settings or drawing ambient settings for a specific command.