• Manufacturing
• AEC
• GIS
• CAD Management
• Cadalyst Magazine
  • Purchase Latest Issue
  • Cadalyst Access Program
  • Magazine Archives (2004-2009)
• E-Newsletters
  • HP Workstation Innovation News
  • Dell Tech Insider
  • Subscribe E-newsletters
• CAD Software & Hardware Reviews
• Features & Columns
• CAD Software Tutorials
  • All CAD Tutorials
  • "Circles & Lines" AutoCAD Tutorial, by Lynn Allen
  • "Learning Curve" AutoCAD Tutorial, by Bill Fane
• CAD Tips & Tools
  • Cadalyst CAD Tips - Tips and Downloadable AutoCAD Code
  • Video Tips Gallery
  • CAD Software Tutorials
  • Cadalyst Benchmark Test
• CAD Video Gallery
• CADspeed: Hardware Blog
• Cadalyst Benchmark Test
• CAD Events Calendar
• Subscriber Services
• Job Search
• Cadalyst Store
• Advertising

Track Geometric Points in AutoCAD

Avatech Tricks Tutorial: Find points in relation to existing geometry without extra geometry.

Editor's note: This tutorial courtesy of Avatech Solutions.

While designing in AutoCAD, you often want to sketch to coordinates that are referenced from existing geometry. AutoCAD offers a few tools that can help with this task and avoid the addition and management of construction lines. Most AutoCAD users are familiar with the object snap (osnap) Extension function — which can be combined with object snap tracking to find needed coordinates from existing geometry — but there are a few more commands and sub-commands that not all users are as familiar with. These commands include From, Point Filters, Temporary Tracking Points, and Tracking. This Tech Tip will explain the use of the last two.

To illustrate these commands, we will use a simple design of a bearing and the machine side plate to mount two of these bearings on.

We want to make sure our AutoCAD osnap settings are correct. For this exercise, make sure Endpoint, Center, Midpoint, Intersection, and Extension are selected as running osnaps. Also be sure the Object Snap Tracking option is enabled on the status bar. For this exercise we will turn off Dynamic Input, either by selecting the icon on the status bar or by pressing the F12 key.

The first task is to place the bolt holes on the bearing flange. These holes are 3 inches from the center of the bearing in both directions. We will use the Temporary Track Point sub-command to place one hole, and then we will pattern the remainder. We want to find the bolt hole center by "temporarily" tracking in two directions from the center of the bearing. Select Center, Diameter from the circle command menu. Hold down the Shift key and press the right mouse button (RMB) to display the osnap override dialog box. Select Temporary Track Point.
 


If you use keyboard shortcuts, press T + T + Enter instead of using the dialog box.

Next is the point in the process where you probably will need to slow down until you can master the process. Do not click the center of the bearing; just hover over it and the center osnap icon, and then move away. You will leave an acquisition point behind. If you hover over the point again, it will be removed — it is a toggle.

Move your cursor along a horizontal line to form the extension dotted line. Best practice is to move either beyond the dimension you want. Enter the first dimension from the keyboard and press Enter. Another acquisition point will show up; resist passing your cursor over it, because that will erase the point. Move your cursor directly above this acquisition point to form a second extension dotted line.


Acquiring the first point (left) and the second point (right).


Enter the second dimension from the keyboard and press Enter. You can now specify the diameter of the circle. Use either a polar or rectangular array to create the remaining holes.
 

1 2 3