Get Aligned with the AutoCAD® Civil 3D® API and Raise Your Profile Partha Sarkar – Autodesk DE219-3 This session is on the creation and management of alignment objects using the AutoCAD® Civil 3D® API. It will cover the creation of siteless alignment, conversion of AutoCAD polylines to Civil 3D® alignments and creation of alignment objects from different combinations of lines, curves and spirals both within and outside sites. You will learn how to add station equations, design speeds and superelevation to alignments. Using a .NET application in the Civil 3D Reports Manager to generate report for an Alignment will be discussed in this session. This session will also cover creation of ground profiles which are used to show surface elevations along a horizontal alignment and to visualize the terrain along a route of interest. You will learn how to create profiles by layouts and how to modify existing profiles. Familiarity with the command interface features of AutoCAD® Civil 3D® and a good knowledge of VB programming are required for this session. About the Speaker: Partha has 10 years of industry experience in the design, analysis, development, and implementation of many civil engineering and geospatial projects and applications. Based in Bangalore, India, he currently works in the Developer Technical Services (DevTech) Division of Autodesk. Before joining Autodesk, he worked for many large-scale infrastructure projects including metro rails, highways, and defense projects. He has a Bachelor’s and Master’s degree in Civil Engineering from Premier Universities in India. [email protected] Aligned with the AutoCAD® Civil 3D® API and Raise Your Profile Introduction This session focuses on understanding the Alignment and Profile objects in AutoCAD® Civil 3D®. Alignment and long sections or profiles are very important entities in Highway / Roadway projects, Storm water drainage / sewer system, Railway, Channel design projects, Land Development project; the list includes many more. In this chapter we are going to explore these two important objects and associated APIs in Civil 3D. Alignment i.e. horizontal alignment consists of straight lines and curves. Curves are fitted to provide a smooth transition between straight sections of the horizontal alignment. Alignment objects can represent centerlines, lanes, shoulders, right-of ways, or construction baselines etc. Creating and defining the horizontal alignment is one of the first steps in roadway, railroad, or site design. Figure 1 – Arial view of a Highway AlignmentFigure 2 – Alignment Object Model Alignments in and outside of Site Alignments are usually created in existing sites. However, Civil 3D 2008 has introduced a new object named AeccAlignmentsSiteless, which allows us to create an Alignment outside of site. In the following screenshot (left side image) we can see an Alignment is created outside of Sites collection, where as in the right side image we can see an Alignment is created in a Site.Figure 3 – Alignment –outside & inside of Sites Irrespective of whether the Alignment is created in a Site or outside a Site, an alignment is made up of a series of entities, which are individual lines, curves, and spirals that make up the path of an alignment. The entities are held in the AeccAlignment.Entities collection. This collection has several methods for creating new entities. Let us try to understand what a Siteless Alignment is. If alignments are placed on a site, they will interact with other objects on the site in two ways: • If an alignment exists on a site with parcels, the alignment will subdivide any parcels it crosses over. • If one or more alignments on a site form a closed region, a parcel will be created from the region. If you do not want an alignment to interact with other objects use this new object - AlignmentsSiteless while creating an Alignment.The AeccDocument object contains a new property called AlignmentsSiteless which contains a collection of alignments. Here is a code snippet which demonstrates how to create Alignment outside of a Site. ' First, we will get the collection of alignments not in a site. Dim oAlignments As AeccAlignmentsSiteless Set oAlignments = g_oAeccDoc.AlignmentsSiteless Dim strAlignName As String strAlignName = "Alignment_SiteLess" ' Create the alignment only if it has not already been created. Dim oAlignment As AeccAlignment If isAlreadyExistsAlign(strAlignName) Then MsgBox strAlignName & " :Alignment is already added " Else Set oAlignment = oAlignments.Add(strAlignName, "alignment", g_oAeccDb.AlignmentStyles.Item("Design Style"), g_oAeccDb.AlignmentLabelStyleSets.Item("Major & Minor")) ' Add the entities to create the alignment geometry Let us now look at alignments which are created in existing sites. Each AeccSite object has its own collection of alignments held in an AeccAlignments object in the AeccSite.Alignments property. The AeccAlignments object provides two ways of creating new alignments. The AeccAlignments.Add method takes an alignment name, a layer to draw on, an alignment style object, and an alignment label style object as parameters and returns a new empty alignment. An alignment is made up of a series of entities, which are individual lines, curves, and spirals that make up the path of an alignment. The entities are held in the AeccAlignment.Entities collection. This collection has several methods for creating new entities. Dim oAlignment As AeccAlignment Set oAlignment = g_oAeccDb.Sites.Item("site1").Alignments.Add(strAlignName, "a-1", oAlStyl, oAlLblStyl) Dim fstLine As AeccAlignmentTangent Set fstLine = oAlignment.Entities.AddFixedLine1(pt1, pt2)The AeccAlignments.AddFromPolyline method takes in addition to those of the Add method, an AutoCAD polyline entity and flags indicating whether curves should be added between the separate line segments and whether the polyline entity should be erased after the alignment is created. Public Sub CreateAlignmentFromPolyline() On Error GoTo ErrLabel Dim strAlignName As String strAlignName = "Alignment_from_Pline" If getCivilObjects = True Then If isAlreadyExistsAlign(strAlignName) Then MsgBox strAlignName & " :Alignment is already added " Else Dim oPoly As AcadLWPolyline Dim oAlign As
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