Recommended test
Build one small symmetrical truss and validate its span, rise and member layout in the preview.
- Open Truss Builder and enter a known bearing-to-bearing span, roof angle and eave.
- Choose A-Frame, set top and bottom chord sizes, and add one mirrored vertical-post pair.
- Read the dimension preview and compare the reported rise with the visible geometry.
- Toggle Connector plates and inspect both faces of the joints. Confirm the plates stay within the timber edges.
- Save the definition with a clear name, add it to the model, and measure the final span.
Define the envelope
Span is measured bearing to bearing. Eave is separate. Roof angle drives rise and top-chord direction, while tail plumb height shapes the rafter end. Enter top-chord, bottom-chord and web sizes using the actual framing dimensions you intend to represent.
Choose a template
A-Frame supports paired vertical posts and optional collar-tie-style geometry, making attic or open-center studies possible. W-Frame creates the familiar web layout and is generally the suggested template below 40 degrees. Template choice is geometry, not an engineering approval.
Read the preview
The preview reports dimensions and updates as inputs change. Check symmetry, heel positions, chord intersections and member overlap before saving. Loft-related readouts can show clear width between webs and available height below a tie.
Add or reuse
You can add the current truss to the model and save its definition to the library for use in Build Generator. Measure the inserted result and inspect its orientation. Structural capacity, connector plates, bracing and fabrication tolerances must be designed outside this geometric tool.
Show connector plates
Connector plates is on by default for new A-frame and W-frame trusses, including the House and Garage quick-start trusses. Toggle it in Truss Builder to show or hide the generated plates. Saved older definitions keep their previous setting; enable the option and save the definition to use it for new trusses.
Compact rectangular nail plates appear on both faces of supported joints and adjust with the timber geometry. They stay within the timber edges. Joints that cannot fit a supported rectangle, or whose members have incompatible thicknesses, are left unplated. These are visual representations, not a structural connector specification.
Plates belong to the truss assembly. Selecting, moving, copying or deleting the truss includes them, and the parts lists count the complete truss. An A-frame dormer opening removes plates where the original joints have been cut away, while plates at intact joints remain.
Existing project geometry does not rebuild on load. Recreate or replace a truss to apply a changed definition, then save and reopen a test project to inspect the result.