Lines, Rectangles and Polygons
Use the SHAPES group, the first of the sketch toolbar's three, to draw everything made of straight edges: points, lines, rectangles and polygons. Reach for it as soon as you are inside a sketch and the outline you need has corners rather than curves. This article is the reference for those tools: what each one asks of you, and what it builds on your behalf.
Take that second half seriously. A rectangle in Kapy is not four independent lines that happen to form a rectangle. It is four lines plus the constraints that keep them one, so dragging a corner leaves you with a rectangle. Almost every tool here works that way, which is why you should reach for them rather than drawing the same shape by hand out of lines.
Point
One click gives you one point. It builds nothing you can extrude. Its whole job is to be referenced: something to snap to, to hang a constraint on, to measure from, to mark a hole centre before you decide how big the hole is.
Line
Click for one end, click for the other. Then keep clicking: the tool stays armed and chains on from the last point, so an outline of six segments is one trip to the toolbar and seven clicks.
Two behaviours shape everything you draw here:
- Near-horizontal and near-vertical get straightened. A segment drawn within about 3° of an axis is snapped exactly onto it and given a horizontal or vertical constraint. You get the alignment you were aiming for, and a constraint that keeps it.
- Escape ends the chain, and so does picking another tool. Every segment you already closed stays. What Escape throws away is only the one still following your cursor.
The three rectangles
All three produce the same thing, four lines held square by constraints, and differ only in what you tell the tool.
| Tool | Clicks | Use it when |
|---|---|---|
| Rectangle | 2 — opposite corners | You know where the outline goes |
| Rectangle from centre | 2 — middle, then a corner | The part is symmetric about a point you already have |
| Rectangle from 3 points | 3 — one edge, then the width | The rectangle is not axis-aligned |
The first two are axis-aligned. Use the 3-point one to draw a rectangle at an angle without rotating it afterwards, since it is the only one that can. All three live on the same toolbar button: the default face is corner-to-corner, and the other two sit behind the caret.
Polygons
Draw a polygon from an edge, not from a centre and a radius. Your two clicks are the two ends of one side, and the polygon is built on it.
Triangle, square, pentagon, hexagon and octagon are the same tool with N fixed. Use the generic Polygon entry to set the number yourself.
What holds the shape together is constraints, not a frame: every side is made equal to the others, and the interior angles are pinned. So one length drives the whole polygon. Dimension a single side, or type it into the S field as you draw, and the rest follows. If you need it dimensioned across the flats or across the corners, the way hex hardware is specified, draw your own construction circle and constrain the polygon to it.
Typing numbers while you draw
Every tool here shows a small field beside the cursor as you drag: L for a line, W/H for a rectangle, S for a polygon's side. Type a number and that dimension is locked. The preview stops being free in that direction and the value becomes a real dimensional constraint on the finished shape.
For a rectangle, press Enter with the fields filled and the shape commits outright. For a line or a polygon it locks the number but still waits for your click, because a length alone does not say which way the shape points.
What each tool leaves behind
| Tool | Key | Emits |
|---|---|---|
| Point | P | One point |
| Line | L | One line per click pair, plus horizontal/vertical where inferred |
| Rectangle | R | 4 lines, 3 perpendicular constraints and a horizontal on the base edge |
| Rectangle from centre | — | 4 lines, 1 perpendicular, a horizontal, and both diagonal midpoints pinned to the centre |
| Rectangle from 3 points | — | 4 lines and 3 perpendiculars, with no horizontal: you chose the base direction |
| Polygon (N) | G | N lines, all sides constrained equal, interior angles pinned |
| Triangle / Square / Pentagon / Hexagon / Octagon | — | The same, with N locked |
Close the outline and it becomes a region, the thing an extrude actually consumes. Circles, Arcs and Curved Primitives covers the rest of the primitives, and the tools that bring in text, artwork and gears are in Text, Artwork and Gears.
See also
- Circles, Arcs and Curved Primitives: circles, arcs and the print-friendly teardrop
- Geometric Constraints: the relations these tools add for you
- Editing Sketch Geometry: changing what you have drawn