Unit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 1 Create Points Overview In this lesson, you learn how to work with points in AutoCAD Civil 3D. Points are one of the most fundamental elements in site development and transportation projects. They can be used to represent existing conditions and proposed construction locations. Point data that represents existing conditions is usually created from survey data files generated from total station survey, GPS, or LiDAR survey equipment. Engineers and construction personnel create points required for construction from design data. Once a design is completed, engineers extract point data from the design, and then send this information to the field for construction staking. Points created during the design are uploaded to GPS and Total Station survey equipment, and used for construction staking. In common terms, a point represents a singular location in space. It is usually characterized with an X and Y (easting and northing) coordinate pair in two-dimensional (2D) space, or an X, Y, and Z (easting, northing, and elevation) coordinate triplet in three-dimensional (3D) space. In Civil 3D, points are represented with a point object, which is an intelligent object with the following properties: - Number - Description - Elevation - Northing Lesson 2 AutoCAD Civil 3D 2010 Education Curriculum Student Workbook Unit 2: Create Ground DataUnit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 2 - Easting Point objects are as shown in the following illustration. The Civil 3D point object consists of a marker and a label. The display of the marker is controlled with a point style. In this illustration, you can see how different point styles can be used to show different types of points. The display of the label is controlled with a point label style. Different label styles can be used to show specific point data. Objectives After completing this lesson, you will be able to: Explain how points are used in different phases of an engineering project. - Describe how to use grips to modify points and point labels. - Describe which objects can be used to create points in a drawing. - Import points from an external text file into a drawing. - Describe how point groups are used to identify characteristics shared by points. - Explain the function of point tables. - Create a description key. - List the guidelines for managing points. - Create points manually. - Create point groups.Unit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 3 Exercises The following exercises are provided in a step-by-step format in this lesson: 1. Import Points 2. Create Description Keys 3. Create Points Manually 4. Create Point Groups About Points You create points from survey data to generate a base plan drawing and a surface object to model the existing conditions. Following the design process, you can also create points from Civil 3D object data that can be used for construction staking. A point represents a singular location in space with elevation, northing, and easting coordinates. It also has properties that represent the point number, a raw (field) description, and an expanded (full) description. For modeling existing conditions, points are typically imported from a text file or created from the survey database. A Civil 3D point object is shown in the following illustration. Point marker Point number Point elevation Point description Point Uses Before the engineering begins, legal surveyors use points to define land parcel boundaries. Points represent the corners of property boundaries and are connected with parcel segments to define the land parcel. During this process, surveyors also use points to representUnit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 4 horizontal and vertical survey control points. These points are referenced when establishing locations for boundary, topographic, and construction surveys. Topographic surveyors use points to define existing conditions prior to design and construction. Existing conditions are represented with a pre-engineering base plan drawing, and an existing ground surface model. The base plan drawing is created with symbols and linework. Symbols are inserted at spot locations such as catch basins, manholes, and power poles. Base plan linework is created by connecting points with similar descriptions, such as edge of pavement and bottom of ditch. The existing ground surface model is created from points that represent the true topography. Points representing manhole inverts and fire hydrant tops are excluded from the existing ground surface model. Designers create points on the design model that can be used for construction staking. Points created on the design model contain description, coordinate, and elevation data that contractors can use to lay out the proposed design for field construction. Examples The following are examples of how points are used in projects. Points are imported from a text file that usually contains point number, northing, easting, elevation, and description. If point numbers are not provided in the text file, they are automatically created during the import. The following illustration shows an external text file with point data. Prior to developing a parcel of land, a boundary survey is completed to define the limits of the parcel boundary. Surveyors use points to show property corners and survey control locations as shown in the following illustration.Unit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 5 Points are also used for pre-engineering topographic mapping and the creation of the existing ground surface model, as shown in the following illustration. Points can also be used for construction purposes. Construction points can be created for road gutter lines and uploaded to a data collector for construction staking, as shown in the following illustration.Unit 2 – Lesson 2: Create Points Civil 3D 2010 Student Workbook ▪ 6 Graphically Editing Points with Grips Often points are created in close proximity to each other. This can make it difficult to read the data associated with the points. You can use grips to control the positioning of labels and other information associated with points. The following illustration shows the grips used to control the display of points and points labels. Rotate point grip Toggle subitem grip Drag point grip
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