In Civil 3D, creating surface boundaries is essential for controlling the extent of your surface and removing unwanted areas.br 🎯 Steps to Create Surface Boundaries in Civil 3D:br Step 1: Open Surface Propertiesbr Go to the Toolspace panel.br Under the Prospector Tab, expand Surfaces.br Select the surface you want to edit (e.g., Existing Ground).br Step 2: Access Surface Definitionbr Right-click on the surface and select "Edit Surface Style".br In the Definition tab, find the Boundaries option.br Step 3: Add a New Boundarybr Right-click on Boundaries and select Add....br In the Add Boundaries Dialog Box:br Name the boundary (e.g., Outer Boundary).br Set Type to Outer, Show or Hide.br For cutting inside areas, use the Hide boundary option.br Click OK.br Step 4: Select the Boundarybr Select the Polyline or feature line that defines your boundary.br Press Enter.br ✅ Surface Updates Automaticallybr Your surface will update, trimming areas outside the boundary.br 🌟 Pro Tips:br For multiple boundaries, add Inner Boundaries or Data Clip Boundaries.br Use Hide Boundaries to exclude unwanted areas like ponds or buildings.