While the Truss tool does not produce log trusses, you can download a Bonus Catalog of Log Truss Components that includes a selection of log trusses ready to be placed in your plans, as well as templates that you can use to create custom truss sizes. This library can be found in the Millwork section of the Chief Architect 3D Library.
This article describes how to use these templates to create a custom log truss with a 22' span and 12/12 pitch.
To create a custom truss envelope
Open a new, blank plan file, then select View> Library Browser if your Library Browser is not already present.
Browse to Bonus Catalogs> Log Truss Components> Log Truss Templates and select the 24' - 12/12 Log Truss Envelope.
Click once in the drawing area to place this CAD block at that location.
Click the Select Objects button, then click on the CAD block to select it and click the Explode CAD Block edit button.
Select Edit> Edit Behaviors> Edit Object Parts from the menu.
Group select the three lines on the right side CAD block: the lines that represent the end of the bottom log, the top edge of the bottom log, and the top of the right-hand angled log.
With these three lines selected as a group, click the Transform/Replicate Object edit button.
In the Transform/Replicate Object dialog
Check the box beside Move.
Specify the X Delta as -24".
Click OK to close the dialog and move the selected objects 24" to the left.
Turn off Edit Object Parts .
Using their edit handles, reconnect the lines of the envelope so that the top edges meet at the new ridge point and the bottom edge snaps to the log end line on the right.
When this is accomplished, the lines will form a closed polyline that, when selected, will h ave a grey fill color.
At this point, the envelope polyline can be used as a guide to customize a truss template.
To modify a log truss template
In the Library Browser, under Bonus Catalogs> Log Truss Components> Log Truss Templates.
Select the 24' - 12/12 Log Truss Template.
Click once to place this architectural block in your plan, near the envelope polyline.
Click the Select Objects button, then click on the truss template to select it.
Use thePoint to Point Move edit tool to align the left side of the truss template with the left side of the envelope polyline. To do this:
Click thePoint to Point Moveedit button.
Click once on the lower left corner of the truss template architectural block.
Click once on the lower left corner of the envelope polyline.
In the image above, the envelope polyline is shown in red for clarity.
With the truss template still selected, click theExplode Architectural Block edit button.
The template's components can now be edited so that the logs on the right side align with the envelope polyline like those on the left side already do.
Select the right top chord log and use the Transform/Replicate Object edit tool to move it 24" to the left (X Deltaof -24"), as described above.
Group select the king post and two angled logs and use the the Transform/Replicate Object edit tool to move them 12" to the left (X Delta of -12").
Using the edit handles, shorten each of the modified logs so they fit within the envelope polyline.
Be sure to shorten the angled logs so they do not extend through the top chords.
To override movement restrictions, you can hold down the Ctrl or Command key on your keyboard while resizing these objects.
Group select the six logs and click the Make Architectural Block edit button to group them back into a single block again.
To convert the template into a symbol
Select 3D> Create Perspective View> Perspective Full Overview .
With the 3D view active, select Tools> Symbol> Convert to Symbol from the menu.
In the Convert to Symbol dialog
Select "Millwork" from the Symbol Category drop-down list.
Make sure that Add to Library is checked.
Check the box beside Show Advanced Options.
On the 3D panel of the Symbol Specification dialog, which opens next:
Select the X Axis radio button under the "Rotation" heading.
Click the Rotate + button one time so the truss is oriented upright in the preview pane.
Type a short, descriptive Name for the new symbol, such as "22' - 12/12 Log Truss".
On the 2D Block panel of the dialog:
Click Generate Block to generate the Truss's 2D CAD Block.
On the Options panel of the dialog:
Specify a Height off Floor. In this example, 102" is used.
Click OK to close the dialog and add the truss as a millwork symbol in your User Catalog.
To save your custom envelope and template
To save your customized truss template architectural block in the User Catalog of the library for future use,select it usingthe Select Objects tool and click the Add to Library edit button.
If you would like to save the 22' Log Truss Envelope polyline in the User Catalog as well, begin by moving the truss template architectural block to a different location.
Select the text object and click the Open Object edit button.
In the Rich Text Specification dialog, change the text to say 22' Log Truss Envelope, then click OK.
Group select the polyline and text, click the Make CAD Block edit button, then click theAdd to Library edit button.