1© 2006 Autodesk Under the Surface: Creating Accurate Surfaces in Civil 3D Scott Wagner, P.E. Business Development Manager

2© 2006 Autodesk Introduction  Who am I?  Why this is important to me?  Poll  Handouts/Questions  Objectives

3© 2006 Autodesk Objectives  Understand how to make a surface in Civil 3D  Understand the theory behind making a surface in Civil 3D  Understand how to perform surface edits  Understand how to apply surface masks  Understand an overall strategy on how to create an accurate surface.

4© 2006 Autodesk Agenda  Differences between Land Desktop Surfaces and Civil 3D Surfaces  Create a Surface from Point Group  Types of Surfaces  Create a Surface from Contours, Point Files & DEM  Surface Evaluation Process

© 2006 Autodesk Under the Surface: Land Desktop vs. Civil 3D I’ll Race You….And I’ll Win!

© 2006 Autodesk Under the Surface: Land Desktop vs. Civil 3D Land Desktop 2007 Demonstration

© 2006 Autodesk Under the Surface: Create a Surface from Point Groups Creating and Viewing Surfaces in Civil 3D

© 2006 Autodesk Under the Surface: Create a Surface from Point Groups Civil 3D 2007 Demonstration

© 2006 Autodesk Under the Surface: Types of Surfaces Tin Surface, Grid Surface and Volume Surfaces

10© 2006 Autodesk TIN Surface The Most Common Surface Type TIN surfaces provide an accurate surface model that is widely used.  TIN Surface- Triangular Irregular Network. A TIN surface is the most common method of interpolating elevation data. The points are connected into triangles that are used to interpolate for contours, and to generate profiles and cross-sections. The lines that make up the surface triangulation are called TIN lines. (Civil 3D Help) Contour Line 543 TIN Lines

11© 2006 Autodesk Grid Surface The Other Method Grid surfaces provide an accurate surface model that is largely used with DEM files.  Grid Surface- A type of surface created from a DEM or SDTS file, or imported from a LandXML file. A grid surface consists of a sampled array of elevations for a number of ground positions at regularly spaced intervals. (Civil 3D Help) “…It is a grid spaced surface in which each regularly spaced cell is assigned a single elevation.” (Autodesk Education Curriculum for Civil 3D 2006)

12© 2006 Autodesk Volume Surface The Surface needed to do Volume Calculations Volume Surfaces can either be TIN or Grid.  TIN Volume Surface- A differential surface created from a composite of points based on base and comparison surface. (Civil 3D Help)  Grid Volume Surface- A differential grid surface based on user-specified base and comparison surfaces. The grid method of volume calculation measures the difference in elevation between two surfaces at each intersection in a user-defined grid. (Civil 3D Help)

© 2006 Autodesk Under the Surface: Create a Surface from Contours, Point Files, and DEM Files Time to go Deeper

© 2006 Autodesk Under the Surface: Create a Surface from Contours Civil 3D 2007 Demonstration

© 2006 Autodesk Under the Surface: Create a Surface from a Point File Civil 3D 2007 Demonstration

© 2006 Autodesk Under the Surface: Create a Surface from a DEM File Civil 3D 2007 Demonstration

© 2006 Autodesk Under the Surface: Surface Evaluation Process A good process yields good results.

18© 2006 Autodesk Surface Evaluation Process Create the Surface With TIN lines on, View the Surface in 3D to look for Spikes Use Contours, Flow Arrows and Gradients to Verify Slopes Look at Boundary Conditions – Add boundaries where Needed Look for Areas where Breaklines can be Added

19© 2006 Autodesk Surface Evaluation Process (cont.) Look for Flat Areas, or where Triangles edges need to be Swapped Apply Masks for Better Performance Peer Review Export to Land XML for Archive of Finished, Ready to use Surface

20© 2006 Autodesk Conclusion  Differences between Land Desktop Surfaces and Civil 3D Surfaces  Create a Surface from Point Group  Types of Surfaces  Create a Surface from Contours, Point Files & DEM  Surface Evaluation Process

21© 2006 Autodesk Contact Information Scott Wagner, P.E.  Address  Ideate Website Address  Additional Civil 3D Webcasts

22© 2006 Autodesk