Engineered Layout Overlays (Truss / I-Joist) Coming
ComingThis feature is designed but not in DimSum yet. This page describes how it will work.
Bring the truss or I-joist layout from the manufacturer into your project, line it up on the plan, and tie its members, marks and counts into your takeoff, 3D and reports.
Overview
Where this fits: in the market, engineered trusses and I-joists are rare; most estimators take off 2x floors, ceilings and rafters themselves many times a day. That's why the Joist & Rafter tools come first and this feature comes later. It still matters for other markets and for multi-family/commercial jobs.
Roof trusses and I-joist floors are usually engineered by the truss or I-joist company, not by the estimator. DimSum is not truss-design software and has no truss tool. What it does is let you use the manufacturer's layout in your takeoff:
- overlay the layout sheet exactly on your plan,
- pick the members into a takeoff instance with count, spacing and lengths,
- read the marks (
T01,T02,GE01,TJI 230 11-7/8) into a count-by-mark table, - link the layout to your floor or roof Assembly, so sheathing, drywall and insulation are still calculated while the members are priced as "by others",
- see the members in 3D and list them in a Truss / I-Joist Summary report.
Where to find it
| Place | What it does |
|---|---|
| Project Tree → Engineered Layout Overlays | Lists the project's engineered layouts |
| Import | Import the manufacturer's PDF/DXF as an Engineered Layout page linked to a Plan Level |
| Page tab → Overlay & Align (4-click) | Aligns the layout onto the plan |
| Extract tab | Pick Line / Trace Path for picking members (see Line extraction) |
| Tool Settings dialog → Assembly tab | Set a framing slot to "By Others – Engineered Layout" |
| Reports tab | Truss / I-Joist Summary starter template |
How to use it
1. Import the layout
- Get the layout from the supplier as a PDF (vector is best) or DXF.
- Import it as an Engineered Layout and link it to the Plan Level it belongs to, e.g.:
- "Roof Truss Layout" → Roof,
- "I-Joist Layout" → Main Level.
- It converts to a DimSum page like any other import and appears under Engineered Layout Overlays in the Project Tree.
2. Line it up on the plan
- Open the plan page for that level (e.g. the roof plan).
- Run Page → Overlay & Align (4-click) with the plan as the base and the layout as the overlay:
- Click point 1 on the plan (e.g. a building corner).
- Click the same point on the layout.
- Click point 2 on the plan (a far corner, for accuracy).
- Click the same point on the layout.
- DimSum moves and rotates the layout onto the plan. If the two scales disagree beyond a tolerance, it warns you and offers to match scale.
- The layout now shows as a tinted overlay on the plan. Toggle it on/off and fade it with the opacity slider.
3. Pick the members into a takeoff
- Click Pick members (Pick Line) or Trace and click the truss/joist lines on the layout. Shift+click adds more.
- DimSum creates an Engineered Members instance (Linear behavior) with count, spacing and lengths.
- Check the count against the layout's own truss/joist count.
4. Read the marks
- Run Read marks. DimSum reads the PDF text near each member (
T01,T02,GE01,TJI 230 11-7/8) and groups the members by mark. - Review the proposed matches in a list and confirm or fix them.
- The result is a count by mark table, e.g.
T01 × 24, T02 × 6, GE01 × 2.
5. Link the layout to your floor or roof assembly
- Open the Floor or Roof instance that sits on these members (e.g. Roof – Trusses – 7/16 OSB – Shingles or Floor – I-Joists – 3/4 Subfloor – 1/2 GWB).
- On the Assembly tab, set the framing slot to "By Others – Engineered Layout" and pick the layout.
- The assembly now:
- uses the layout's spacing and depth for its other layers (sheathing, drywall, insulation, subfloor position),
- uses the layout's elevations in 3D,
- prices the members as supplied by others, or from a quote amount you enter.
6. Check it in 3D
- Open a 3D pane.
- The engineered members appear at their level with the layout's depth, drawn as typical profiles (not the engineered truss geometry).
- Use the section box to check that the sheathing, ceiling drywall and walls line up with them.
7. Report it
- In the Reports tab, run Truss / I-Joist Summary.
- It lists marks, counts, spans, and anything by others, alongside the rest of the takeoff.
Options & settings
Engineered Layout page
| Setting | What it does | Default |
|---|---|---|
| Linked Plan Level | The level the layout belongs to (Roof, Main Level…) | Chosen at import |
| Alignment | 4-click alignment to the base plan page | Not aligned until you run it |
| Overlay visible | Show/hide the tinted overlay | Not set in plan |
| Overlay tint / opacity | Color and fade of the overlay | Not set in plan |
Engineered Members instance
| Property | Meaning |
|---|---|
| Count | Number of members picked |
| Spacing | Spacing detected between members |
| Lengths | Length of each member (and totals) |
| Marks | Count by mark (after Read marks) |
| Supplied by others / quote amount | How the members are priced |
Assembly slot option
| Setting | Meaning |
|---|---|
| Framing slot = "By Others – Engineered Layout" | Use the layout's spacing/depth for layers and its elevations for 3D; price members as by others or from a quote |
Examples
Roof trusses
- Import "Roof Truss Layout.pdf" → link to Roof → 4-click align on the roof plan.
- Pick all truss lines → Engineered Members: 32 members at 24" spacing.
- Read marks →
T01 × 24,T02 × 6,GE01 × 2. - Roof assembly framing slot → "By Others – Engineered Layout": roof sheathing, underlayment and shingles come from the Pitched Area; the ceiling drywall layer uses the truss spacing; trusses are priced from the supplier's quote.
- Truss / I-Joist Summary shows the three marks with counts and spans, flagged "by others".
I-joist floor
- Import "I-Joist Layout.pdf" → link to Main Level → align on the main floor plan.
- Pick the joist lines → count, 16" spacing, individual lengths. Read marks →
TJI 230 11-7/8. - Floor assembly joist slot → "By Others – Engineered Layout": the layout's depth (11 7/8") sets where the 3/4" subfloor sits, so subfloor sheets, glue and the drywall ceiling below are still calculated. The joists themselves are by others.
- In 3D, the joists show at the Main Level with an 11 7/8" depth.
Tips & shortcuts
- Ask the supplier for a vector PDF or DXF. Scanned layouts can be overlaid, but members and marks can't be picked from them in v1.
- Align using two corners that are far apart for the best accuracy.
- Fade the overlay while picking so you can see both the plan and the layout.
- Use Color On/Off on the plan so the layout tint stands out.
- Keep the layout's mark list open next to the count-by-mark table to check counts quickly.
Rules, limits & edge cases
- Not truss design. DimSum doesn't design, check or size trusses or I-joists. The manufacturer's layout is the source of truth.
- No truss tool (decision #19).
- 3D shows typical profiles, not engineered webs, chords or heel geometry.
- Scanned layouts: you can overlay and align them, but picking members needs vector linework (scan line detection is later), and mark reading relies on PDF text.
- v1 instances live on one page.
- If the layout's scale disagrees with the plan beyond the tolerance, you're warned at alignment and offered a scale match.
- Revised layouts: load the new layout as a new page version. The old version is never deleted; view one, both overlaid, or switch fully to the new one, then re-pick or check the members against it.
Related features
- Overlay & Align (4-click)
- Line extraction (PDF & CAD)
- Assemblies
- Joist & Rafter tools (for framing you do take off yourself)
- 3D viewport
- Report Designer (Truss / I-Joist Summary)
- Plan import & auto-conversion
- Page Versions (layout revisions)
