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Creating Arcs by Best Fit

Product Documentation
Intermediate
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Use the create arc by best fit command to use a series of AutoCAD Civil 3D points, AutoCAD points, existing entities, or clicks on screen as a basis to create an AutoCAD arc.

The best-fitting curve through the points is calculated. You can then use a dialog box to exclude any of the specified points or to select one or two pass-through points.

Note

When using the best fit commands for profile design, use the Create Parabola command for vertical curves. See Vertical Curve Design for more information.

To create an AutoCAD arc by best fit from AutoCAD Civil 3D points

  1. If you are creating a best fit arc for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
  2. Click Home tabDraw panelBest Fit drop-downCreate Best Fit Arc.
  3. In the Arc By Best Fit Dialog Box, select From COGO Points.
  4. Select three or more points. Enter G to select a point group or N to enter points by number.

    As you select points in the drawing window, a white X marks each regression point and a temporary, dashed arc is displayed in real time.

    Note

    You must select at least three non-collinear regression points.

  5. Press Enter to complete the command.
  6. In the Panorama window, use the Regression Data vista to make changes to the regression points.

    As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.

    Note

    When the AutoCAD arc is created, it will not retain any link to the regression points.

  7. Create the AutoCAD arc:
    • Click to create the arc and keep the regression data. You may then use the data as a basis to create more arcs.
    • Click to create the arc, clear the regression data, and close the Regression Data vista.
  8. If desired, convert the AutoCAD arc to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.

To create an AutoCAD arc by best fit from AutoCAD points

  1. If you are creating a best fit arc for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
  2. Click Home tabDraw panelBest Fit drop-downCreate Best Fit Arc.
  3. In the Arc By Best Fit Dialog Box, select From AutoCAD Points.
  4. Select three or more AutoCAD points.

    As you select points in the drawing window, a white X marks each regression point and a temporary, dashed arc is displayed in real time.

    Note

    You must select at least three non-collinear regression points.

  5. Press Enter to complete the command.
  6. In the Panorama window, use the Regression Data vista to make changes to the regression points.

    As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.

    Note

    When the AutoCAD arc is created, it will not retain any link to the regression points.

  7. Create the AutoCAD arc:
    • Click to create the arc and keep the regression data. You may then use the data as a basis to create more arcs.
    • Clickk to create the arc, clear the regression data, and close the Regression Data vista.
  8. If desired, convert the AutoCAD arc to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.

To create an AutoCAD arc by best fit from existing entities

  1. If you are creating a best fit arc for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
  2. Click Home tabDraw panelBest Fit drop-downCreate Best Fit Arc.
  3. In the Arc By Best Fit Dialog Box, select From Entities. Specify the tessellation and mid-ordinate tolerance settings.
  4. Select one or more of the entities listed at the command line.
    Note

    You may select several types of entities listed at the command line.

    As you select entities in the drawing window, a white X marks each regression point and a temporary, dashed arc is displayed in real time.

    Note

    You must select at least three non-collinear regression points.

  5. If you selected a profile object, specify the starting and ending station on the Specify Station Range Dialog Box.
  6. Press Enter to complete the command.
  7. In the Panorama window, use the Regression Data vista to make changes to the regression points.

    As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.

    Note

    When the AutoCAD arc is created, it will not retain any link to the regression points.

  8. Create the AutoCAD arc:
    • Click to create the arc and keep the regression data. You may then use the data as a basis to create more arcs.
    • Click to create the arc, clear the regression data, and close the Regression Data vista.
  9. If desired, convert the AutoCAD arc to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.

To create an AutoCAD arc by best fit by clicking on screen

  1. If you are creating a best fit arc for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
  2. Click Home tabDraw panelBest Fit drop-downCreate Best Fit Arc.
  3. In the Arc By Best Fit Dialog Box, select By Clicking On The Screen.
  4. Select a starting point and at least two other points.
    Note

    You may use OSNAP or transparent commands to select points.

    As you select points in the drawing window, a white X marks each regression point and a temporary, dashed arc is displayed in real time.

    Note

    You must select at least three non-collinear regression points.

  5. Press Enter to complete the command.
  6. In the Panorama window, use the Regression Data vista to make changes to the regression points.

    As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.

    Note

    When the AutoCAD arc is created, it will not retain any link to the regression points.

  7. Create the AutoCAD arc:
    • Click to create the arc and keep the regression data. You may then use the data as a basis to create more arcs.
    • Click to create the arc, clear the regression data, and close the Regression Data vista.
  8. If desired, convert the AutoCAD arc to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.

Ribbon

Home tab Draw panel Best Fit drop-down Create Best Fit Arc

Menu

Lines/Curves menuCreate Best Fit EntitiesCreate Arc

Command Line

CreateArcByBestFit

Dialog Box

Arc By Best Fit

Specify Station Range

Regression Data Vista


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