Start with the box
Most disappointing results come from what the capture box contained, not from the matcher.
- Include the symbol and its own label. If the device is marked with a letter or a code, that mark is part of what makes it that device.
- Leave a little room. A box drawn slightly wider than the symbol is safer than one that clips a stroke.
- Do not box two symbols at once. A box around a device and its neighbour describes a pair, and only pairs will match.
- Zoom in first. A symbol a few pixels across cannot be outlined accurately.
ZeroCount already discounts a good deal of what a box merely catches: a wall line or a pipe run passing through, a neighbouring arc, ceiling grid ticks, anything larger than the symbol itself, and any mark whose ink carries on past the edge of the box. Those are treated as background rather than as part of the symbol.
If a capture returns one result — just the copy you drew around — the box has almost certainly caught something unique to that copy. Draw it again, tighter, keeping only the device and its label.
How labels are handled
Symbols carry text: a ring with a letter, a box with a code, a sensor with a circuit number. Whether that text is part of the symbol's identity or just information about one copy is decided across the drawing, not by you.
- When the text is the only thing naming the device, it is required. Outline a ring marked "W" and you get the "W" rings, not the "A" rings and not the bare ones.
- When the device already has a fixed name, a varying mark beside it is treated as information. A sensor marked "PIR" carrying a different circuit number on each copy is one device, and a single capture finds them all.
- Text that merely sits nearby is ignored. A room name or a note clipped by a slightly wide box is not read as a label.
- A template that carried a label only matches copies that carry one. A bare shape is a different symbol from the same shape with a letter beside it.
- Labels stay upright. A device rotated along a wall keeps its label the right way up and often on a different side. ZeroCount looks for the label at the right distance in any direction, so those copies still match.
One visible consequence: marker boxes can be different sizes within one group. A copy carrying its letter above rather than beside it needs a taller, narrower box. That is correct, not a fault.
If some copies are left out because they do not carry the label you outlined, a message reads No matching labelled symbols with the number skipped.
Messages that explain a short count
"Blank Template Detected"
"The selected region appears to be blank." The box held no ink. Zoom in and draw again over the symbol itself.
"Using standard detection"
The precise vector search could not use this capture, so the older image-based detector ran instead. Results still arrive, after a short scan. It happens when:
- the box holds only lettering — a code or a word with no shape around it;
- the shape is only one or two strokes, which is too little to describe a symbol reliably;
- there is no vector ink under the box at all.
The image detector is less precise about labels and, on a second run, can place duplicate markers on copies that are already marked. If you see this message repeatedly on one drawing, include more of the surrounding shape in the box, or count that symbol by hand.
"No additional detections found"
"All matches for this symbol are already marked on the drawing." On a vector drawing, a repeat capture never duplicates markers that are already there, so this usually means the group is complete.
"No matching labelled symbols"
Copies were found but skipped because they do not carry the template's text label. If they should have been included, capture one of the unlabelled copies as its own group.
Things that quietly limit a count
Work through these when a count is short and the box looks right.
| Check | Why it matters |
|---|---|
| AoIs on the drawing | Detection is restricted to inside them, even when they are hidden. Open AoIs, Legends & Zones and look at the list. See Areas of interest. |
| Ignored colours | Ink you have removed is invisible to the capture. If part of the symbol is in an ignored colour, the capture cannot see it. See Cleaning up the drawing. |
| Remove Background | Helpful on most sheets, but it takes pale colourless ink out. On a drawing whose services are drawn in grey, turn it off. |
| Already-marked copies | Vector detection skips symbols that already carry a marker, so a second run legitimately returns fewer than the first. |
| The detection engine in use | See below. |
Rotated and mirrored copies
On a vector drawing, symbols are read from the drawing's own geometry, so copies placed at any angle — or mirrored — are found and marked at their true positions and rotations. You do not need a separate capture for the rotated ones.
On an image drawing the detector sweeps through rotations instead, which works but is less exact. If rotated copies are being missed on a scanned sheet, capture one of them as a second template into the same group. See Adding to an existing group.
Switching the engine for a drawing
The left-most button in the workspace header shows which engine the drawing is using: for vector, for image. Hover it and the tooltip explains what is in use and why.
Clicking it switches that drawing to the standard image detector. Use it when a drawing is technically vector but the vector search keeps refusing captures — a PDF exported in an unusual way, for example. The choice applies to that drawing only.
On a drawing that is genuinely image-based the button is greyed out, with the explanation This drawing is image-based (scanned or converted) — the standard image detector is used.
See Vector and image drawings.
Older uploads with no paper information
Drawings uploaded before ZeroCount started recording paper size cannot run the whole-drawing scan or the vector takeoff tools. You will see Missing paper-size info for this file (legacy upload) on the greyed Auto Takeoff items, or This file has no paper-size information when a scan is refused.
There is no way to add the information to an existing upload. Upload the drawing again and it is recorded on the way in. Auto Count Symbol still works on the old copy in the meantime.
A working order for a difficult sheet
- 1
Turn on Remove Background and look at what is left. See Cleaning up the drawing.
- 2
Sample away any other trade's colour that crosses your symbols.
- 3
Draw a legend rectangle if the sheet has a symbol key, and run Auto Detect Symbols to see what is there.
- 4
Count the rest one at a time with Auto Count Symbol, watching the live preview count before you release.
- 5
Top up the stragglers with Detect New Symbol into the group, or place them by hand.
Next steps
- Detect New Symbol — the capture procedure and the live preview.
- Cleaning up the drawing — Remove Background and Ignore Colours in full.
- Adding to an existing group — a second template usually beats a second group.
- Counting manually — when to stop fighting the matcher.
- Troubleshooting — problems that are not about detection.