Precision, measurement, and guides

Models made in Hew tend to get manufactured: 3D printed, cut, assembled. Exact dimensions are first-class. They come from typed input on every tool, from the display units you choose, and from construction guides that extend the snapping system.

Units

Model geometry is always stored in meters internally. Settings ▸ Units controls how lengths are displayed and interpreted:

System	Format	Example
Metric	Meters	1.2375 m
Metric	Centimeters	123.75 cm
Metric	Millimeters	1237.5 mm
Imperial	Architectural	5' 3-1/8"
Imperial	Fractional inches	63-1/8"
Imperial	Decimal inches	63.125"

Precision (also in Settings ▸ Units) sets how far a readout is rounded, separately for each format, and marks a rounded value with ~; choose Exact to see every digit a length needs (see Settings). The examples above are values that need no rounding. Every readout — tool previews, the Tape Measure, the typed-input echo — follows this setting.

Typed input, in full

While a tool is mid-gesture, type a value and press Enter. The rules:

• Bare numbers are read in the current display unit (in imperial modes, bare numbers are inches).
• Explicit units always win, in any display mode: 250mm, 3.5cm, 1.2m, 2km, 6", 6in, 2', 2ft.
• Feet-inches-fractions parse whenever ' or " appears: 5'3", 5' 3-1/2", 3 1/2", 5/8".
• Rectangle takes two comma- or x-separated dimensions, width across the surface then height up it, mixable: 1cm,100mm, 2' x 18"; one value makes a square.
• Rotate and Protractor take plain degrees; Scale takes a plain positive factor as-typed (not a length in the display unit) — or an explicit length (50mm, 8") as a target dimension for the axis being dragged.

Clicking is the same as typing. A value you click is exactly the value the measurement box shows, as if you had typed it: if the box reads 9.399 mm × 3.787 mm when you click the second corner, the rectangle is exactly that size, not a few extra digits’ worth off. This holds for every tool with a readout, on the ground and on a face. The exception is a click that snaps onto existing geometry (an endpoint, midpoint, intersection, point on an edge, guide point, center, or quadrant): that keeps the exact point you snapped to, because rounding it would land a hair off the geometry you aimed at. Only free picks, on a face, on a plane, or along an axis lock, are rounded to the displayed value.

Tape Measure (T)

The Tape Measure does two jobs, chosen by where your first click lands:

Measure a distance. Click any point, move, and read the live distance; click again to finish. If the second click lands on empty space, Hew drops a guide point there and — when the two points aren’t the same — an infinite guide line through both of them, the same pair SketchUp drops. If the second click lands on real geometry, you get only the measurement; nothing is created. Hold ⌘/Ctrl through either kind of click to measure without dropping anything, for whenever you only want the readout.

Both jobs also take a drag: press on the first point or the edge, drag, and let go where the second click would go.

Drop a parallel guide. Click on an edge — of a solid, a sketch you’ve drawn, a group member, or a component instance — then move sideways. A guide line parallel to that edge follows at the offset shown in the readout. Click to place it, or type an exact offset and press Enter. This is the classic SketchUp workflow for laying out a design before drawing it. The line where a face of one object meets a face of another (the On Intersection Line cue) works the same way, even though no edge is stored there; its middle and ends are points, so a click on them measures instead. A world axis works as the source edge too: click anywhere along the red, green, or blue axis (the On Axis cue confirms the pick) and pull sideways. So does an existing guide line — one guide can father a whole ladder of parallels.

Working off the ground plane

Neither job is stuck on the ground plane:

• Hover a sketch first and the guide or measurement stays in that sketch’s plane, the same as the draw tools.
• Nothing hovered? Press an arrow key while the tool is idle to lock the next click to a world-axis plane — →/←/↑ for red/green/blue, ↓ or the same arrow again to release. Handy for measuring across, or guiding off, a face that isn’t the ground and has nothing else to hover first.
• Source edge doesn’t lie flat in the active plane? Hew derives the nearest plane that does contain the edge, rather than dropping the constraint outright.
• Clicking an edge that also sits on a face, with no hovered sketch or plane lock, offers that face’s own plane instead — but only while the cursor stays over that same face. Drag off it and the guide falls back to the plain sideways offset.

Once a plane is locked, from any of these sources, a guide or measurement can still reach a point that sits slightly off it — an endpoint or midpoint that doesn’t lie exactly in the plane. A measurement projects that point onto the plane; a parallel guide keeps only the point’s component along the guide’s own direction. Either way, the inference chip marks the snap “projected,” so you know it isn’t landing on the point’s literal position.

Locking the direction mid-gesture

Arrow keys also lock the guide or measurement’s own direction while you’re drawing it:

• Parallel guide: →/←/↑ locks the offset to red/green/blue (↓ releases). An axis that runs along the source edge itself is refused, with a status-bar note explaining why.
• Plain measurement: every axis is fair game, since there’s no edge to run along.
• Shift does the same job without committing to it. Held mid-gesture, it latches onto whichever axis the guide or measurement is currently running closest to, and lets go the moment you release it. An arrow-key lock, once set, survives a Shift tap the same way.

Whichever axis is active, the measurement preview colors to match it — and for a parallel guide, so does the connector line back to the source edge (the guide line itself stays neutral, since it always runs parallel to the edge rather than to the locked axis). The lock reads at a glance instead of off the numbers.

Reading and resizing after the fact

The corner widget keeps showing your last reading after you finish a measurement or place a guide. It doesn’t clear until you switch to a different tool, so there’s time to actually read the number instead of catching it out of the corner of your eye.

You don’t have to type the target length while the gesture is still live. Measure two real points normally, look at the finished distance sitting in the widget, then type a new length and press Enter. Hew offers the same “resize the model?” confirmation this produces mid-drag, only triggered after the fact instead of during. Esc at that point drops the typed number and puts the original reading back, without disturbing anything; typing again still offers to resize against the same two points.

If a group or component is open for editing when you confirm that resize, it resizes just that container instead of the whole model. The dialog names it (“Resize Group 1?”, “Resize Door?”) rather than asking about the model, and the resize is anchored at the first point you measured from, so that point doesn’t move. A component resize reaches every placement of it, since they share one definition; a group resize touches only that group’s contents. Geometry outside the open container stays put either way, and so does the camera — only a whole-model resize moves the view to match. Step out (Esc) with the new size in place, same as any other edit made inside a group or component.

Protractor

The Protractor (Tools ▸ Protractor) measures an angle and drops an angular guide line through a point:

1. Position the on-screen disk. It lies on the face under your cursor, or the ground plane. Hold Shift to lock the current plane, or press an arrow key to force the plane’s axis (→ X, ← Y, ↑/↓ Z).
2. Click the apex (where the angle’s corner sits).
3. Click along a baseline (the zero direction).
4. Sweep to the angle (it snaps near the axes) and click, or type degrees and press Enter.

The apex and the baseline also take a drag: press on the apex, drag along the baseline, let go, then sweep and click as before.

The result is a guide line through the apex at that angle.

Working with guides

Guides are construction geometry — dashed lines and point markers that are never part of your solids and never export, but always snap. Use them to pre-plan positions, then draw to them.

• The purple “On Guide” snap cue appears whenever the cursor is on a guide.
• Where a guide crosses an edge, a sketch line, or another guide, the amber Intersection cue appears — click there to land exactly on the crossing, which is usually the whole reason the guide exists.
• View ▸ Guides hides or shows all guides at once; hidden guides don’t snap.
• To move a guide, use Move: with no objects selected, click the guide and click (or drag) to where it goes — axis locks and typed distances work as for objects, and the guide is selected only while it moves. Tap the copy modifier to drop a copy instead, then type 5x or 5/ for a row of evenly spaced guides.
• To turn a guide, use Rotate: with nothing selected, set the pivot on the guide and sweep. To turn a guide about a point on another guide, or where two guides cross, select it with Select first: with a guide selected, Rotate’s first click only places the pivot. A rotated copy with 6x or 6/ fans copies around the pivot.
• To delete one guide, select it with the Select tool and press Delete. Edit ▸ Delete Guide Lines clears every guide in one undoable step.
• Guides are saved in the .hew file, and guides in imported SketchUp files come across. A SketchUp guide that starts at a point or runs between two keeps that length, so it draws and snaps only there, as it does in SketchUp. A guide from a SketchUp file carries the tag its layer became, so hiding that tag in the Tags panel hides the guide, and a Scene that hides the tag hides it too; select a guide to see its tags in Object Info.

Reading precision from the model

For a quick sanity check without any tool gymnastics: select an object and read Object Info (its Volume, Surface area, and Size are there too), or use the Tape Measure between two snap points. Endpoint-to-endpoint measurements come from the model’s exact geometry.