Wall tools, Opening tool & Cut tool Coming

ComingThis feature is designed but not in DimSum yet. This page describes how it will work.

Draw a wall line once and the Wall behavior measures everything about it (length, height, corners, T-intersections, ends, openings, net area) as base properties; you build the studs, plates, sheathing and everything else as your own parts, list-matched to your own table items. The Opening tool cuts windows and doors into walls, and the Cut tool splits any member-based shape.

Overview

A Wall tool is drawn like any Linear tool: the line on the plan is the Wall Plane. It usually carries an Assembly (see Assemblies), an ordered stack of layers (siding, sheathing, studs + insulation, drywall) positioned around the Wall Plane, which places the layers correctly in 2D and 3D.

Nothing is hard-coded

It only measures the wall's geometry and exposes it as base properties: {Length}, {Height}, {Runs}, {L-Corners}, {T-Intersections}, {Ends}, {Opening Count}, {Opening Width Total}, {Wall Area}, {Net Wall Area}, {O.C.}…

You build every material as a part. For example, a "Studs" part with the formula

RoundUp({Item > Length} / {Item > O.C.}, 0) + 1 + {Item > L-Corners} * 2

To still work out of the box, the optional Walls example library (pre-checked at setup) contains ready-made wall tools whose parts already have example formulas and list matches. Copy one and change it; delete it if you don't want it.

Walls aren't only for wood framers: a metal-stud partition, a CMU wall or a demising wall uses the same behavior with different parts and a different assembly.

The Opening tool places windows and doors on walls: it cuts the wall's layers, deducts their area, and exposes each opening's size so your own header / king / jack / cripple parts can count from it.

The Cut tool is a shared utility that splits beams, joists, rafters, wall plates and linear shapes at a point or along a cut line.

Where to find it

• Tools panel → DimSum Defaults → Walls (example library): Wall Tool (assembly-driven); Exterior Wall 2x6, Interior Wall 2x4, Plumbing Wall 2x6, Knee Wall, Pony Wall, Gable End Wall (drawn on an elevation face), Shear Wall; Opening Tool.
• Tool Designer → Tools → New → Behavior = Wall to build a wall tool from nothing.
• Takeoff ribbon → Cut for the Cut tool.

How to use it

Draw walls

1. Arm a wall tool (e.g. Exterior Wall 2x6).
2. In the Tool Settings dialog (if prompted), check the Assembly, the Stud Material slot, Wall Height (default {Level > Plate Height}) and O.C. spacing.
3. Check the Placement reference (default Exterior face of studs).
4. Click along the wall line (continuous or segment mode). Pick Line and Trace Path work too. Backspace picks up the previous point; N starts a new run in the same instance.
5. Press Tab while drawing to flip which side is exterior. A preview shows the layers on the correct side.
6. Press Enter to finish the run. Keep drawing runs; L-corners, T-intersections and free ends are detected where walls meet.
7. Esc stops the tool.

Build a wall tool from scratch (walkthrough)

This is the "build your own" path. The example library does the same thing for you, ready to copy.

1. Tool Designer → Tools → New, base type Linear, Behavior Wall. Name it "Ext Wall 2x6 – 9'".
2. Base Properties tab: tick the wall measurements you want visible: Length, Height, L-Corners, T-Intersections, Ends, Opening Count, Net Wall Area.
3. Custom Properties tab: add what your rules need, e.g. Plate Count (number, default 3), Stud Size (dropdown from the Dimensional Lumber list, default 2x6), Wall Type (dropdown from a Wall Types list; the tool's color can follow it, e.g. "Ext 2x6 10'" = Dark Teal).
4. Parts tab, add:

• Studs: Qty RoundUp({Item > Length} / {Item > O.C.}, 0) + 1 + {Item > L-Corners} * 2 + {Item > T-Intersections} * 2. List Match: Stud list, Nom. Size = {Item > Stud Size} AND Wall Height = {Item > Height} → e.g. "2x6x104 5/8 Stud".
• Plates: Qty RoundUp({Item > Length} * {Item > Plate Count} / 16, 0). List Match: "2x6x16".
• Sheathing: Qty RoundUp({Item > Net Wall Area} * (1 + {Waste %}) / 32, 0), Waste % list-linked to the 10% default. List Match: "7/16 OSB 4x8".
• Drywall, Insulation, Housewrap, Nails, Labor (optional): same idea, each reading the wall's base properties.

5. Use the Condition Builder or a decision-table list for anything with branches (e.g. treated bottom plate only if {Item > On Slab}).
6. Tools Playground: draw a sample wall with a corner and a window and check every quantity. Coming Save to your .tsum.

Change the reference on one run

Select one wall shape → Properties → Placement reference → e.g. Centerline. It's marked ◆ (shape override). The drawn line doesn't move; the layers re-stack around it.

Different heights on one level

A 12' great-room run in a 9' wall instance: select the run → Height → 12'-1 1/8" (◆), or make a second instance. Height defaults to the level's plate height; the override flows into every part that reads {Item > Height}, so the stud list match picks the longer stud automatically.

Place an opening (window or door)

1. Arm the Opening Tool (or a tool you built from it, like "Window 3050").
2. Set Width, Height and Sill or Head height (typed, or asked for when the tool is placed — tick Input on the property).
3. Click on a wall where the opening goes. It snaps to the wall line.
4. The wall's layers are cut and their area deducted. The wall's {Opening Count} and {Opening Width Total} update. The opening shows in 2D and 3D.
5. Header, king, jack and cripple quantities come from parts you build on the Opening tool (the example library includes a set), reading the opening's own Width, Height and Sill.

On an elevation page, place openings on a face to cut siding/sheathing there.

Cut tool (shared)

1. Arm Cut from the Takeoff ribbon.
2. Optional: set a Gap (e.g. the width of a beam, or 0 for a simple split).
3. Click a member or shape to split it at that point, or drag a line to cut everything it crosses.
4. Each piece gets its own length (and its own label for beams).

Works on Beam, Joist, Rafter, Wall plates and Linear shapes.

Options & settings

Wall base properties (what the behavior measures)

Property	Meaning
{Length}	Total drawn length of all runs (at the drawn reference line)
{Height}	Wall height (default {Level > Plate Height}; per-instance/shape override)
{Runs}	Number of separate runs (shapes)
{L-Corners}	Corners where two wall runs meet end to end
{T-Intersections}	Places where another wall's end meets this wall mid-run
{Ends}	Free wall ends (not joined to another wall)
{Opening Count}	Openings placed on this wall
{Opening Width Total}	Sum of opening widths
{Wall Area}	Length × Height, one side
{Net Wall Area}	Wall Area minus opening areas
{O.C.}	The spacing setting (for your formulas)
…	Plus the Linear base properties (Linear Total, Volume, 3D Length…) and any custom properties you add

Corner counts follow the ownership rule below: the wall drawn first owns a shared L-corner, so {L-Corners} never double-counts across two instances. Other properties may still be added (e.g. per-side net areas, opening area); see the open questions.

Placement reference

Set on the wall tool and overridable per shape:

Reference	The drawn line is…	Typical use
Exterior face of studs (default)	the outside of the framing (sheathing goes outside the line)	Most common: tracing the stud line on plans
Centerline	the center of the studs	Interior partitions, CAD centerlines
Interior face of studs	the inside of the framing	Tracing from inside dimensions
Exterior finish face / Interior finish face	the outermost / innermost layer	Tracing overall wall outlines
Custom offset	any distance from a chosen layer	Special cases

Tab flips which side is exterior. Each shape remembers its own reference and side, so one wall instance can mix them.

Corners between two walls

When two wall instances meet at an L-corner, the wall drawn first owns the whole corner. It counts in that wall's {L-Corners}, and the second wall counts nothing there — so a corner is never counted twice and never split in half. No formula gymnastics ({L-Corners} / 2 and the like) are needed.

• Ownership is recorded when the corner forms, and it stays with the first wall even if the second one is edited later.
• Delete the owning wall and the corner passes to the remaining wall.
• Select a corner and choose Reassign corner if you want the other wall to own it.

Snap points on every shape

So the second wall lands exactly on the first, every drawn shape exposes snap points:

Snap point	Where
End	Each end of a run
Corner	Each corner in a polyline run
Face	The wall's exterior and interior faces (and each layer face)
Centerline	The middle of the studs
Midpoint	Halfway along a run

Hover shows the snap marker and its name; snapping to one makes the join exact, which is what lets the corner, T-intersection and end counts be right. Snap types and tolerance are set in Settings → Canvas & Drawing.

Per-shape settings

Setting	Instance default	Per-shape override
Placement reference	✅	✅ ◆
Exterior side (flip)	✅	✅ ◆
Base Elevation	Level (see the level elevation model in 3D settings)	✅ ◆
Height	{Level > Plate Height}	✅ ◆ (e.g. a lower garage run, a taller great room)
Vertex elevations		✅ ◆ (e.g. a raked gable run)
Assembly, slots, spacing, layers, parts	✅	— (instance only)

Wall settings (Tool Settings dialog)

Setting	Default
Assembly	From the tool
Dynamic slots	e.g. Stud Material: 2x4 / 2x6 / 2x8
Wall Height	{Level > Plate Height}
Base Elevation	Level elevation
O.C. spacing	16" (used by the assembly's framing layer and by your formulas via {O.C.})
Exterior side	Flip with Tab
Include/exclude layers	All on
Custom properties	Whatever your tool adds (Plate Count, Wall Type, Treated Bottom Plate…)

Opening settings

Setting	Meaning
Width, Height	Rough opening size
Sill / Head height	Position in the wall
Counts	Opening count by size (e.g. "3050" × 6), for reports and schedules
Parts	Yours: header, kings, jacks, cripples, trim, flashing… built with formulas on the opening's properties

Cut tool settings

Setting	Default
Mode	Click (single point) or drag (cut line across many)
Gap	0

Examples

Framing: 2x6 exterior wall with a window (user-built rules)

One run: 40'-0", Height 9'-1 1/8" (109 1/8"), O.C. 16", both ends are L-corners, one T-intersection, one window 3'-0" × 5'-0" RO. Assembly: 7/16" OSB | 2x6 studs + | 1/2" GWB.

What the behavior measures (no rules involved):

Property	Value
{Length}	40'-0"
{Height}	9'-1 1/8"
{L-Corners}	2
{T-Intersections}	1
{Opening Count}	1
{Opening Width Total}	3'-0"
{Wall Area}	40 × 9.094 = 363.75 sf
{Net Wall Area}	363.75 − 15 = 348.75 sf

What one user built (EXAMPLE formulas; your rules may differ, and DimSum has none of its own):

Part	Example formula	Result	List match
Studs	RoundUp({Item > Length} / {Item > O.C.}, 0) + 1 + {Item > L-Corners} * 2 + {Item > T-Intersections} * 2 + {Item > Opening Count} * 4	30 + 1 + 4 + 2 + 4 = 41	"2x6x104 5/8 Stud" (decision table: 9'-1 1/8" wall with 3 plates → 109 1/8 − 4 1/2 = 104 5/8")
Plates	RoundUp({Item > Length} * {Item > Plate Count} / 16, 0) with Plate Count = 3	120 LF ÷ 16 = 7.5 → 8	"2x6x16"
Sheathing	RoundUp({Item > Net Wall Area} * (1 + {Waste %}) / 32, 0), Waste % = 10%	383.63 ÷ 32 = 11.99 → 12	"7/16 OSB 4x8"
Drywall	RoundUp({Item > Net Wall Area} * (1 + {Waste %}) / 48, 0)	383.63 ÷ 48 = 7.99 → 8	"1/2 GWB 4x12"
Insulation	RoundUp({Item > Net Wall Area} / 75, 0) (75 sf/bag sample)	348.75 ÷ 75 = 4.65 → 5	"R21 Batt"

On the Opening tool, the same user built: Header length {Width} + 3" = 36 + 3 = 39" (3'-3"), List Matched to a header table by width (e.g. 2-ply 2x10 up to 4', a sample value); Cripples RoundUp({Width} / 16", 0) * 2 = RoundUp(2.25) × 2 = 3 × 2 = 6. Note that the Studs formula above already counts the opening's 2 kings + 2 jacks through {Opening Count} * 4; you choose where each part is counted, just don't count it twice.

Placement reference: same line, different stacks

2x6 wall, OSB 7/16", GWB 1/2" (offsets from the drawn line, + = exterior):

Reference	OSB	Studs	GWB
Exterior face of studs	0 → +7/16"	0 → −5 1/2"	−5 1/2" → −6"
Centerline	+2 3/4" → +3 3/16"	+2 3/4" → −2 3/4"	−2 3/4" → −3 1/4"
Interior face of studs	+5 1/2" → +5 15/16"	+5 1/2" → 0	0 → −1/2"

Commercial: metal-stud partition

Interior partition, 3 5/8" 20 ga metal studs @ 16", Centerline reference, 60' long, 10' high, drywall both sides, no openings. The user's parts:

• Studs: RoundUp({Item > Length} / {Item > O.C.}, 0) + 1 = RoundUp(720 ÷ 16) + 1 = 45 + 1 = 46
• Track (top + bottom): RoundUp({Item > Length} * 2 / 10, 0) = 120 LF ÷ 10' = 12 pieces
• Drywall: RoundUp({Item > Wall Area} * 2 / 48, 0) = 600 sf × 2 = 1,200 ÷ 48 = 25 sheets (4×12, no waste in this formula)

Cut tool: concrete footing pours

A 140 LF Linear footing is split with the Cut tool at a construction joint 80' along → two shapes of 80' and 60' in the same instance, so each pour can be reported.

Tips & shortcuts

• Start from the example Exterior Wall 2x6 and change its formulas rather than building from nothing.
• Put your framing rules in decision-table lists (wall height + plate count → stud item) instead of long IF chains.
• Drive the wall color from a Wall Type list so every "Ext 2x6 10'" wall is Dark Teal automatically.
• Trace the stud line on the plan with the default reference; switch single runs to Centerline only where the plan dimensions to centers.
• Watch the layer preview while drawing and press Tab before finishing if the exterior is on the wrong side.
• Put openings on walls before reviewing sheathing counts; they deduct area.

Rules, limits & edge cases

• DimSum never adds studs, plates, headers or cripples on its own. A wall tool with no parts produces measurements only.
• Vertical wall planes come from Linear walls with Height (plan pages) or from Area tools on elevation pages; "Wall from line" is a later item.
• The Gable End Wall variant is drawn on an elevation face.
• An opening must be placed on a wall (plan) or on a face (elevation page).
• Shear Wall variants carry their own sheathing and nailing properties (as custom properties).

Related features

• Assemblies (wall example, constraints)
• The DimSum Defaults tools & "out of the box vs. build your own"
• Parts
• Dynamic Lists & the Advanced Part
• Beam tool (headers)
• Joist & Rafter tools (overrides, cuts)
• Instances & Shapes (per-shape overrides)
• Materials Library
• Elevation Faces & Face Align