Joist Extension

This capability requires Dimension Premier or the Extensions Add-on.

This document describes joist extensions. Joist extensions have all the functionality of normal (formula) extensions, plus they calculate and display a series of parallel members inside the measurement. The Joist extension can be used for more than joists. Any measurement that needs a layout of parallel members can use it. For example, beams, rafters and rake walls. The following parameters can be specified for a joist extension:

Figure 1: Sample Joist Extension

The members are drawn using the point color and twice the line thickness.

Creating Standard Joist Extensions

If no standard joist extensions exist, you can create a joist extension using Standard Extension Maintenance. Simply press the "Add" button in the Standard Extension List Window and select "Joist" from the context menu. The Standard Extension will be displayed with three rows predefined.

Figure 2: Joist Standard Extension Maintenance

The three pre-defined rows are:

The name and position of the predefined rows can't be changed. Otherwise, the information can be edited as described for Standard Extension Maintenance.

Other rows can be added after the predefined rows. These rows can use formulas with any of the measurement values (Area, Count, Length, Perimeter) or the predefined rows (Spacing, Rounding, and Pitch) or any of the following calculated values:

Figure 3: Standard Joist Extension with Additional Calculations

Editing a Measurement's Joist Information

The formula part of a joist extension can be edited the same way as other extensions. This is described in Extension Measurement Maintenance. You can also move and rotate the joist layout. To start this, right click on the measurement and select "Edit Extension" from the context menu. Then select "Move/Rotate Layout and Edit Joists..." from the sub-menu. The Move/Rotate Toolbar will be displayed over the measurement as shown in figure 2.

Figure 4: Sample Joist Extension with Move/Rotate Toolbar

The toolbar has four buttons:

Editing Joist Members

While the Move/Rotate bar is displayed, you can edit the individual joist members. Right click on a member and ro display the editing options below:

Figure 5: Member Offset Edit Window

When you insert or move a joist, the Member Offset Edit Window is displayed. This allows you to specify the exact desired offset. The offset can be entered and displayed in several formats:

The offset of the first calculated joist in a measurement in equal to the joist spacing. So if the spacing is 16 inches, the first joist offset will be 16 inches, the second will be 32 inches, etc.

Figure 6: Measurement with inserted and deleted joists

Edited joists are displayed as follows:

Displaying Length Counts

Figure 7 Joist Length Counts Window

You can display the counts for each length by right-clicking on the measurement and picking "Edit Extension/Display Member Counts..." from the context menu. The Joist Lengths Count Window will be displayed as shown in figure 7. The list has three columns:

  1. The number of members of a given length
  2. A blank column (reserved for the material description)
  3. The length of the members

The first row will have a number of "R/L" (for Random Lengths) with a length equal to the total length of all members. The remaining rows will show the count and length for each different length used.

It's frequently useful to copy the member counts to another application (such as Excel). To do this, press the "Copy to Clipboard" button. A grid of information (in tab-separated format) will be copied to the clipboard. The columns will match those shown in the list.

You can then switch to the receiving application and paste the grid.