Eraser

🧽 The Eraser (E) removes part of what you have measured. Quantities update as soon as you erase, so the group total always reflects what is actually on the drawing.

Use it to trim a fill that reached too far, to cut an opening out of an area, or to remove a strip that turned out to belong to another material.

Two families of eraser

Shape modes erase whatever falls inside a shape you draw. Use these when you know the area to remove by eye.

Region modes erase using the same detection the region tools use, so you can remove a detected area rather than tracing it. Use these when what you want gone has a natural boundary on the drawing.

Shape modes

Mode	Key	Use it for
Polygon	1	An irregular area, clicked corner by corner
Box	2	A rectangular strip or block
Drag Circle	3	A circle you size by dragging
Circle	4	A fixed circle, good for repeated small removals
Brush	5	Painting away freehand, for fiddly edges
Ellipse	6	An elliptical opening

Box and Polygon cover most work. Reach for Brush when an edge is irregular and precision matters more than speed.

Region modes

Mode	Shortcut	Use it for
Region	⇧R	Removing a whole detected area in one click
Sweep	⇧S	Removing along a swept path
Multi	⇧M	Removing several detected areas in one action
Expand	⇧X	Removing an area and growing outward from it
Free Trace	⇧F	Tracing the outline of what to remove

Region (⇧R) is the one to know. If your paving fill picked up a planting bed, one click on the bed removes exactly that bed without you tracing around it.

Boundary and Cutouts

The eraser can adjust the edge of what it removes, targeting either:

• Boundary, the outer edge of the area
• Cutouts, the edges of holes within it

Use this to clean up a fill that stopped a fraction short of a boundary, or that left a thin fringe around an opening, without erasing and refilling.

How quantities update

Erasing recalculates the affected group immediately.

• Area drops by the amount removed.
• Perimeter is recalculated, since erasing changes the shape’s edges. Cutting a hole into an area increases its net perimeter, because the hole’s edge is now part of the boundary.
• Volume follows the new area at the same depth.

If you erase all of a region, it is removed from the group entirely rather than lingering as a zero.

Undoing an erase

Each work in progress group has its own Undo and Redo, stepping through operations on that group alone. So an erase you regret on one material can be reversed without disturbing anything measured since.

Getting a clean result

Zoom in before erasing. Erasing is precise work and the boundary you leave behind is the boundary that gets measured.

Prefer Region mode where a boundary exists. Tracing by hand around something the drawing already defines is slower and less accurate than letting the tool follow it.

Check the total afterwards. The group total is the quickest confirmation that you removed what you intended and nothing more.

Erase rather than delete and redo. Erasing part of a region keeps the rest of your work intact, and is almost always faster than starting the area again.

Common questions

Can I erase across several regions at once? Yes. A shape erase affects every region it covers, which is useful for clearing a strip that crosses materials, so check what is underneath before dragging a large box.

Does erasing affect the drawing? No. It only removes takeoff. The PDF underneath is never modified.

I erased a hole in the middle of an area. Is the hole excluded from the area? Yes. The area is what remains, and the hole’s edge is included in the net perimeter.

Can I erase a count marker? Count markers are removed by deleting them from the panel or on the drawing rather than with the eraser, which works on areas and lengths.