Why a per-group scale exists
The toolbar scale at the top of the editor is the drawing default — every Linear and Area marker on the drawing uses it unless told otherwise.
But sometimes the same drawing carries content at different scales:
- A detail callout drawn at 1:25 inside a 1:100 floor plan.
- Two superimposed plans at different scales (rare but happens).
- A drawing that's been spliced from two source PDFs at different scales.
For these, the drawing-wide default isn't enough. Linear and Area groups can override it on a per-group basis.
Where the per-group scale shows
Expand a Linear or Area group in the sidebar. Next to the group label you'll see the group's current scale — usually the drawing default. Click it to open the scale dropdown for just that group.
The dropdown shows the same presets as the drawing-level selector, plus the calibration option. Pick a different ratio and only that group's markers are reinterpreted.
The drawing's main scale stays unchanged — only this group uses the override.
Setting a different scale on a group
- 1
In the sidebar, click the scale value next to the group's label.
- 2
Pick a preset, or choose Custom to enter a manual ratio or calibrate from a known distance.
- 3
Confirm in the "Update existing groups?" dialog if you have markers already — ZeroCount asks because changing the scale recalculates each marker's reported length or area.
The group's markers update immediately. The Excel export's Scale column for this group reflects the new ratio.
When you'd actually do this
In practice, per-group scale overrides come up most often when:
- You've drawn Linear markers on a detail callout while the toolbar was still set to the main plan's scale. The markers are wrong. Rather than re-do them, change the group's scale to match the callout.
- You're mixing layout-scale and detail-scale items in the same project but didn't want to split them into different drawings.
- You want to demonstrate the impact of a scale change without committing it project-wide.
Most projects don't need per-group scales — keeping the drawing default consistent and using one scale per drawing is simpler.
What it doesn't fix
- A calibration issue — calibration applies to the whole drawing, not just one group. If linear measurements come out consistently wrong across all groups, calibrate the drawing rather than overriding each group.
- Detection or Unit groups — they don't have a scale. Detection and Unit counts are pure integers.
Width (Unit groups only)
Unit groups don't have a scale, but they do have a Width property — the size at which each Unit marker is drawn on the canvas. See Unit width.