Transforming Geometry
Move, Copy, Rotate, Scale, Mirror, Stretch and Array — reposition, duplicate and resize what you have already drawn, and build grids, rings and runs of copies.
Seven commands reposition and duplicate existing geometry. They are built the same way, so learning one teaches you most of the others.
Prerequisites
- You can select objects — see Selecting Objects.
What they all have in common
Three habits carry across every command in this chapter.
They work on a selection. If something is already selected, the command uses it. If nothing is, the command asks you to pick objects first — click or box them, then press Enter to move on.
(One subtlety: a selection you pick inside a command is cleared when the command ends. A selection you made before starting it survives, ready for the next command.)
They ask for a base point. A base point is the handle the change works from — the spot that stays put when you rotate, or the point you drag from when you move. Pick it with an object snap on something meaningful, like a corner or a centre, and the result lands exactly where you intended.
They undo in one step, however many objects they touched or copies they made.
Move — M
What it does. Moves objects from one point to another.
- Pick the base point.
- Pick where it should end up, or type how far —
@500,0moves everything 500 to the right.
For a nudge, you do not need the command at all: with objects selected and nothing running, the arrow keys move them one grid snap step.
Copy — CP
What it does. Places copies, one after another. Pick a base point, then pick a point for each copy you want. The command stays running until you press Enter or Esc, so you never restart it between copies.
| Option | Key | What it does |
|---|---|---|
| Array | A | A row of a set number of copies, spaced by the next point you pick |
| Undo | U | Takes back the last copy |
All the copies you made undo together, as one step.
Copy is not the clipboard
Two different commands share the name, which catches everyone out once.
Modify ▸ Copy (
CP) duplicates within the drawing, placing each copy where you click.Edit ▸ Copy (
Ctrl+C) puts things on the system clipboard for pasting somewhere else — see Moving and Duplicating a Selection.
Rotate — RO
What it does. Turns objects about a base point.
Pick the base point, then type the angle or point the way you want it to face. Enter reuses the angle shown, which is the last one you used.
Positive angles turn counter-clockwise.
| Option | Key | What it does |
|---|---|---|
| Reference | R | Give the angle it is at now, then the angle it should be at |
| Copy | C | Leaves the originals alone and turns a copy |
Reference saves real time. When something sits at an unknown skew and you want it straight, you do not have to measure the angle first: pick along its current edge as the reference, then type 0 for where it should be.
Scale — SC
What it does. Enlarges or shrinks objects about a base point.
Pick the base point, then type the factor (2 doubles it, 0.5 halves it) or point that far away. Enter reuses the factor shown.
| Option | Key | What it does |
|---|---|---|
| Reference | R | Give a length it has now, then the length it should be |
| Copy | C | Leaves the originals alone and scales a copy |
Reference again avoids arithmetic. "This wall measures 3870 and should be 4000" scales correctly without you working out that the factor is 1.0336.
Common and costly mistake: Scale is not about printing
Scale changes how big things are — their real, measured size.
To change how big the drawing prints, set the drawing scale instead.
Scaling geometry to make it fit on paper is the classic beginner error, and it quietly makes every dimension in the drawing wrong.
Mirror — MI
What it does. Reflects objects across a line — for symmetrical halves, handed pairs and anything flipped.
Pick two points to define the mirror line.
| Option | Key | What it does |
|---|---|---|
| Delete originals | D | Replaces the objects instead of keeping them. Remembered between uses |
Tip: turn Ortho on (F8) while picking the two points, and your mirror line is guaranteed perfectly horizontal or vertical.
Stretch — ST
This is the one that behaves differently from the rest, and the one worth taking a minute over — it is enormously useful once it clicks.
What it does. It moves some points of your objects while leaving others anchored, so shapes get longer, wider or deeper rather than simply travelling.
How to use it: drag a box (or click its corners) around the points you want to move, then give a base point and a second point.
- Points inside the box move.
- Points outside it stay exactly where they are.
- An object lying wholly inside the box just moves, as you would expect.
An example. Put a crossing box over the right-hand end of a rectangle and stretch it 500 to the right. The right-hand corners travel; the left-hand ones do not; the rectangle is now 500 wider. That is how you lengthen a room, widen an opening or deepen a bay without redrawing anything.
If you make a selection before starting, only that selection stretches.
Array — AR
What it does. Copies objects in a regular pattern: a grid, a ring, or a run along a path. Think parking bays, bolt holes, balusters, ceiling tiles.
Every step previews the whole pattern as you set it up, and Enter accepts the value shown.
| Kind | Key | What it asks for |
|---|---|---|
| Rectangular | R | Columns, rows, then the spacing of each — type it, or move the cursor and click |
| Polar | P | The centre, how many items, and the angle to fill. Rotate items (I) turns each copy to follow the ring |
| Along path | A | The path, then how many items. Align (L) turns each copy to follow the path |
Associative arrays
Associative (S) is on by default, and it makes the whole pattern a single object.
Why that is good: select it afterwards and you can change the number of columns, rows or spacing in the Properties panel, or by dragging its grips. The array rebuilds itself. Decided you want three bays instead of two? Type 3.
This is the closest thing in Pingendum 2D to parametric behaviour — the array remembers how it was made, so it can be re-specified later.
If you would rather have plain, independent copies, either turn Associative off before you start, or Explode the array afterwards.
Whichever kind of array you used is remembered for next time.
Which one do I want?
| You want | Use |
|---|---|
| To reposition something | Move |
| A few copies at chosen spots | Copy |
| A regular grid, ring or run along a path | Array |
| To lengthen or reshape part of an outline | Stretch |
| To straighten something skewed | Rotate with Reference |
| To make something a known size | Scale with Reference |
| A symmetrical half | Mirror |
| To land two points onto two other points | Align |
Next Steps
Next: Cleaning Up Geometry
Moving and Duplicating a Selection
Cut, Copy, Copy with Base Point, Paste and Paste in Place — moving geometry between drawings, between windows and into other programs, and what travels with it.
Cleaning Up Geometry
Trim, extend, offset, round and bevel corners, break, join, lengthen, explode, convert and reorder — the Modify tools that turn rough geometry into a finished drawing.