Polylines: one object, many segments
A polyline is a chain of line and arc segments stored as one object. It is the right tool for outlines, walls, boundaries and anything you will offset or measure.
In this lesson you will
- Draw polylines with line and arc segments
- Know when to use a polyline instead of lines
- Join and explode objects
- Measure areas and lengths of closed polylines
Why polylines
A polyline behaves as a single object: select it once, offset it in one step, read its total length and — if closed — its area in Properties. Rectangles and polygons are polylines already. Use polylines for building outlines, room boundaries, property lines and walls you intend to offset.
Drawing a polyline
Options also include Width (a thick line with a start and end width — handy for arrows) and Halfwidth.
- 1Type
PL(PLINE) and pick a start point. - 2Draw segments exactly as with LINE (coordinates or direct distance).
- 3Type
Ato switch to arc segments;Lto switch back to lines. - 4Type
Cto close, or press Enter to finish open.
Editing polylines
- Grips: select a polyline to see square grips at vertices and rectangular grips at segment midpoints. Hover a grip for options like Add vertex or Convert to arc.
- PEDIT (
PE): open or close, join, change width, fit a curve.
- JOIN (
J): join touching lines and arcs into one polyline.
- EXPLODE (
X): breaks a polyline back into separate lines and arcs.
Measuring
Select a closed polyline and read Area and Length in Properties. The AREA command (object option) and MEASUREGEOM do the same. For room areas in square metres when drawing in millimetres, divide the area by 1 000 000.
KitWren's free area converter turns square millimetres, metres, feet and more into whichever unit your client needs.
Quick reference
| Command / tool | How to start it | What it does |
|---|---|---|
| PLINE | PL | Draws a polyline |
| PEDIT | PE | Edits polylines (join, close, width) |
| JOIN | J | Joins objects into one |
| EXPLODE | X | Breaks polylines and blocks into parts |
| AREA | AA | Measures area and perimeter |
Common mistakes
JOIN won't combine lines.
Ends must touch exactly. Zoom in; use FILLET with radius 0 or EXTEND to close gaps.
Area looks enormous.
It is in square drawing units. 12 000 000 mm² = 12 m².
Exercise
Room outline and area
- Draw a room outline 5000 × 4000 with PLINE, with one corner cut at 45° (1000 each way).
- Close it.
- Read its area in Properties and convert it to m².
- Draw four separate lines forming a rectangle, then JOIN them into one polyline.
You should end up with: A closed room polyline and its area in m² (19.5 m²).
Checklist
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Lesson quiz
A closed polyline shows its area in the Properties palette.
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Free KitWren tools that help
- Area ConverterConvert square metres, square feet, acres, hectares and more.
- Length ConverterConvert between metres, centimetres, millimetres, kilometres, inches, feet, yards and miles.
- Angle ConverterConvert degrees, radians, gradians, arcminutes and turns.
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