Why clean a drawing up
A services drawing is rarely just services. Underneath your symbols sits the architect's floor plan — walls, furniture, ceiling grids, room hatching — usually screened back in pale grey. Over the top may run two or three other trades in their own colours.
All of it is ink, and detection has to reason about it. A capture box that catches a grid line or a wall corner has to decide whether that mark is part of the symbol. Most of the time it decides correctly, but on a busy sheet the extra ink is what turns a clean count into a patchy one.
ZeroCount has two tools for taking ink out of the picture. Both change what detection sees and what the canvas shows. Neither changes the PDF.
| Tool | What it removes | When to reach for it |
|---|---|---|
| Remove Background | Pale, colourless linework across the whole drawing | The architectural background is drowning the services |
| Ignore Colours | One colour you point at | Another trade's services are in the way |
Both live in the same place: in the sidebar, above the marker list, the Ignore Colours & Remove Background button. The button is highlighted whenever anything is switched on.
Remove Background
The switch at the top of that dropdown strips the pale, colourless ink from the drawing — the screened-back architectural layer, furniture, grids, hatching — and leaves the darker and coloured ink alone.
- 1
Click Ignore Colours & Remove Background in the sidebar toolbar.
- 2
Switch Remove Background on.
- 3
Wait for the drawing to redraw. Processing colours... appears while it works.
You can also toggle it from the keyboard with CTRL+B (CMD+B on a Mac), without opening the menu.
The setting is saved against the drawing, so it is still on the next time you open it, and it applies to detection as well as to the canvas. Turn it off if it takes away something you needed — on drawings where the services themselves are drawn in grey, it will.
Try Remove Background before you start picking out colours. It is one switch, it costs nothing to undo, and on most services drawings it is the single biggest improvement you can make to what the detector sees.
Ignore Colours
Where Remove Background handles the pale layer, Ignore Colours handles a specific colour you point at — the other trade's ductwork running across your sheet, the red fire line through a pipework layout.
You do not type a colour code. You show ZeroCount an example on the drawing and it works out which ink you meant.
- 1
Open Ignore Colours & Remove Background .
- 2
On the Ignore Colours header row, choose how you want to sample: Box drags a rectangle, Polygon clicks point to point.
- 3
Click New. The menu closes and the cursor becomes a crosshair.
- 4
Draw round a short stretch of the line or symbol whose colour you want gone. A small sample is enough.
- 5
Release. Processing colours... appears, and that colour disappears from the drawing.
Each sample you take is added to the dropdown as a small thumbnail under Colour Groups:. Take as many as you need — one per colour you want out of the way.
Only the colour you boxed is removed. Grey linework, text and other services crossing your sample box are left alone, so a box that clips a neighbouring line does not wipe out half the drawing.
Sample the ink, not the space around it. Draw round a length of the line itself. A box mostly full of white paper gives the sampler very little to work with.
Removing a colour group again
Hover a thumbnail in the Colour Groups: grid. A red appears over it and the tooltip reads Click to remove colour group. Click it and that colour comes back.
There is no undo here, but taking the sample again is quick.
What it changes
Both tools affect what detection can see, on vector and image drawings alike:
- Ink you have removed cannot produce a match. That is the point — a symbol that shares its shape with the other trade's fittings stops being confused with them.
- Ink you have removed is also invisible to a capture. If you outline a symbol and part of it is in an ignored colour, that part is not treated as belonging to the symbol. Usually helpful. Occasionally it is why a capture suddenly returns one result.
- The canvas shows what detection sees. The drawing you are looking at is the drawing being searched, so if something looks wrong on screen it will be wrong in the results too.
If a capture that used to work starts returning almost nothing, open this dropdown and check what is switched on. An ignore-colour group taken over a symbol that shares its ink with a service line is the usual culprit.
Bringing settings across from another drawing
Colour groups can be copied between drawings rather than sampled again on every sheet. In New Takeoff › Import › Import from Files , the Ignore Colours section lists the colour groups on the other drawings in the project; tick the ones you want and import them with everything else. That window has its own Remove Background switch, which starts from whatever the current drawing is set to.
See Importing from other drawings.
Common issues
"Some colour masks failed to load"
One or more of the saved colour groups could not be read. The message says how many. The rest have been applied, so the drawing is partly cleaned. Remove the failed group and sample it again.
"Failed to process ignore colours"
The drawing could not be reprocessed at all. Reload the drawing and try again.
The colours came back after a reset
Actions › Reset Drawing clears ignore-colour groups along with everything else on the drawing. Remove Background, which lives with the drawing's other settings, is kept. See Resetting a drawing.
Next steps
- Detect New Symbol — run the capture again on the cleaned-up drawing.
- Detection tips — the other reasons a count comes back short.
- Auto Detect Symbols — a clean drawing gives a much shorter, more useful scan list.
- Importing from other drawings — copy colour groups across a set of sheets.
- Resetting a drawing — what a reset does and does not clear.