Repository navigation
canvas
Home > Canvas basics
< Previous: Your first pattern | Next: Points >
Pan, zoom, toggle the grid and axes, snap while drawing, and select objects in the modeling window.
The modeling window is where you draw and edit geometry. It shows a live drawing surface with a background grid and a pair of axes through the origin. Everything you build stays editable, so learning to move around and select cleanly is the foundation for everything else.
To move the view, drag with the middle mouse button. This pans the canvas without disturbing your drawing or your selection, so you can reach for it at any time - even in the middle of placing a point.
The scroll wheel zooms, and it zooms toward the cursor: point at the detail you want to inspect and roll in, and that spot stays under your pointer as the view scales up. Roll the other way to pull back out. Because zoom follows the cursor, you rarely need to pan and zoom as separate steps - aim, then zoom. Zoom goes deep - up to 800x - so you can work at fine detail without the geometry losing precision.
The window is split down the middle, with the modeling surface on the left and the node editor on the right. The divider between them is draggable: grab it and slide to give either side more room. Both canvases re-fit their contents live as you drag, which is handy when you want to frame a design for a screenshot.
View > Actual Size, or Cmd-0, zooms so one millimeter of your drawing is one millimeter of glass. Hold a ruler up to the screen and the drawing measures true. The view center stays where it was.
To do that, Locus has to know how big a pixel is on your monitor. It asks the system, which usually knows from the monitor's own data, and the status bar reports the density it used. When the system gives nothing usable, Locus falls back to a nominal 96 pixels per inch and tells you the size is a guess.
Fix that in Preferences > Interface > Screen calibration. A bar is drawn at what Locus believes is 100 mm, or 4 inches if that is your unit. Hold a ruler to it and drag the slider until the bar measures true. Each monitor keeps its own setting, and the row follows the window when you drag it to another screen. Reset returns to what the system reports, and is greyed out when there is nothing to return to. Dragging the bar back onto the system's own figure is read as not calibrated rather than as a calibration that agrees, so the override is dropped.
The background shows a world-space grid with light minor lines and emphasized major lines, plus the two axes through the origin - the X axis is a muted red, the Y axis a muted green. The grid is adaptive and unit-aware: its spacing follows the same tidy 1 / 2 / 5 steps as the rulers, in your current display unit (mm, in, ft, or m), so a grid line always lands on a round number. As you zoom in it subdivides to a finer step and as you zoom out it coarsens, and the grid lines line up exactly with the ruler ticks - so the grid doubles as a real-world ruler at any zoom.
Note
The grid and axes are reference guides only. They never appear in exports or affect your geometry.
Schematic mode (View > Schematic, ⌘Y) reduces the drawing to a simplified schematic - filled shapes become flat grey placeholders with clean hairline edges, so you read structure over styling. While it's on:
- Grey placeholder fills. Every filled shape is washed a flat, light neutral grey: its own fill and color set aside - so solids read as plain filled blocks, not styled artwork.
- One constant hairline. Every edge becomes a single thin line of the same width, ignoring each object's stored weight and the zoom level: so a 0.13 mm nib and a 2 mm nib read identically, and nothing thickens as you zoom in.
- No dashes. Dashed styles draw solid; schematic mode is about the shape, not its decoration.
- Reads against the theme. The hairline is black on a light canvas and white on a dark one, and ghost previews turn plain grey: so it always stands out.
Selection still recolors a line, so you can pick and edit as normal with schematic on. It's a view - it changes nothing about your geometry or styles, and toggling it back off restores every fill, weight, and dash exactly as they were.
While a point-placing tool is active, the canvas watches where your cursor lands and previews the smartest place to drop the point. You'll see one of three cues, in the order the click prefers them:
- An orange dot means the point will snap onto an existing point.
- A blue crosshair means the point will land exactly on a crossing of two objects, and it binds to both: so it stays on the intersection as either object moves.
- A green ring means the point will bind to the object under it as a slider, free to move only along that object.
If none of those apply, you get a plain free point. Intersection is always preferred over a slider, so a crossing reliably gives you a two-parent intersection point rather than a point stuck to just one object.
When two points sit exactly on top of each other, the snap takes the one you can see. Hidden points are still snappable, and a construction is full of them, especially once auto-hide has done its work, but a visible point on the same spot wins. Only when both are visible, or both hidden, does the older of the two take it.
Turn Alignment Snaps on from the View menu and the canvas starts offering dotted snap lines that line your cursor up with points that are already there. They are horizontal and vertical only, so a snapped position is the crossing of at most one of each.
Lines arrive two ways, and they coexist:
- Acquired. Hover over a point for a moment and it becomes a reference: its lines stay live while you work, whatever the cursor does next. This is the deliberate one, the reason the feature exists, because you choose what to line up with. Hover over an acquired point again to release it. Two references is the limit, and past two the oldest falls off: two lines can define any crossing, and a third only puts more lines under the cursor.
- Proximity. When you happen to come level with something, the app offers that line unasked, the way other drawing tools do. Chatty by design.
- Hold Alt to suppress the snapping.
When both offer the same coordinate, the acquired one wins: you asked for it.
Hidden points count as references. Auto-hide puts most of a construction's points away as soon as they have been used, and that is exactly the geometry worth lining up with. A hidden point becomes faintly visible while a snap line is running to it, so you can always see what you are lining up with. Scaffold points, the internal plumbing behind ticks and struck arcs, never count.
A snap line is not a guide. Guides are objects you drag off a ruler and can lock, hide and select; snap lines are transient, appear only while you are drawing, and never become part of the model.
A plain click selects one object. Click empty space to deselect. Selection is ordered and supports multiple objects, which matters for tools where the order you pick things in changes the result (booleans, for example).
To build up a selection, hold Shift and click to add more, or hold Command (Control on Windows) to toggle a single item in or out. When several objects overlap under the cursor, a small chooser pops up listing every candidate - points first, then other objects top-most first - so you can pick exactly the one you mean instead of guessing.
Drag across empty space to rubber-band a box, and the direction you drag sets the rule:
- Left to right is a window selection (drawn as a solid blue box): it grabs only objects that fall entirely inside.
- Right to left is a crossing selection (drawn as a green dashed box): it grabs anything the box touches, even partly.
Hold Shift while you drag to add the marquee's catch to your current selection instead of replacing it.
Tip
Everything you select stays highlighted, and a hidden object that you've selected still shows so you can see what you picked. Selecting the same objects is also the starting point for most construction tools - see Points and Lines, rays & segments.
Right-click empty canvas to relaunch whichever drawing tool you used most recently - the same AutoCAD-style repeat you'd expect from a right-click with nothing selected. It only fires over blank space: right-click an object and you get that object's own context menu (a dimension, for instance, offers to switch its type) instead.
Return / Enter does the same thing from the keyboard, and it survives pressing Esc first - Locus remembers the last tool you drew with even after Escape drops you back to Select, so Return brings it right back. Either way, the repeat is blocked while a command is mid-gesture (a multi-click pick, a tick session, a partially-placed dimension), so it can never strand half-built geometry. See Keyboard shortcuts for the full key.
< Previous: Your first pattern | Next: Points >