For today’s topic I wanted to bring back to mind some AutoCAD features that save time for selecting points.

Here’s the link to point tracking in AutoCAD.

Here are a few situations where using snap tracking or point filters are invaluable:

1.  Use the router to line up pipe along the top of steel or beside another pipe.

2. Placing objects a distance from a fitting (like a weld-o-let 3” from an elbow or tee).

3. Locating equipment.

Let’s walkthrough an example of the first scenario in these steps-run a new line 6” away from an existing line, run the new line 6” past the turn, and then change the elevation so the new pipe BOP matches TOS.

Here are the steps for starting a new line 6” off of the second.

1. Set Size = 2”, and spec = 150.

2. Turn polar tracking on (F10).

3. Make sure Snap Tracking is on.

4. Start the ROUTER command (RT).

5. Hover over the existing pipe centerline until a “+” plus appears.  This is a temporary tracking point.

6.  Type 6 and hit enter to start the router line 6” to the right of the existing pipe.

The next section is probably the most technically challenging.  When we used the snap tracking, we were able to give the prompt 2 coordinates (the X and the Z, and then with tracking pick the third (Y).  However, on the turn we don’t have any objects that can give us 2 coordinates (we need the Y and Z now).  We will have to use a feature called the “FROM” command modifier in combination with point filters or coordinate filters.  We will start out by isolating our yz coordinates by using the .YZ point filter.

1.  Enter .YZ at the command line (you should still be in the router prompt).

2.  Drag in the + or – x direction and pick.  This steps freezes our Y,Z coordinates to the direction we want.

3. Now we can use the FROM modifier to select our X coordinate.  Enter FROM at the command line (it’s also on the Shift+Right-click shortcut menu).

4. For the base point prompt, we are going to pick the center line of the existing pipe that is vertical, turning up in the rack.  Now, our selection is even with the pipe turning up in the rack, but 6” south of the existing pipe.

5.  For the offset, we are going to input a relative value, so enter @6,0,0.  The “@” symbol indicates a relative point input.  Now our segment is drawn 6” past the existing pipe turn.

The final step is to line up the bottom of pipe (BOP) with the top of steel (TOS).  To do this we will change the router to the BOP position, and then set the elevation we need.

1. Still in the router command, hit “P” for position.

2.  At the option prompt, enter BOP for bottom of pipe.

3.  Hit enter again to accept the default size (we set it at the beginning).

4.  Hit “E” for the Elevation option.

5. In the elevation change prompt, hit “P” to pick an elevation from the model and pick a point on the top of steel.

Finish the router off by dragging down the pipe rack and selecting an end point and hit enter.  Run the ROUTETHRD command to draw the pipe along the router line we drew.

I’ve posted a video  showing the steps in real-time so you can follow a long.  Happy routing!

Special thanks to Denis Richard for his musical contribution.