Where image processing meets CAD.
The tools cross the boundary between the photo and the drawing: image-aware drawing, geometry-aware correction, and measurement that flows through the whole pipeline. Your corrected, scaled photo stays visible beneath the geometry; toggle it, adjust its brightness, or zoom in with the loupe.
Everything here is free to use. Pro adds multi-view and 3D export. Pricing →
Draw, edit, dimension, and clean up.
- Drawing primitives. Polyline, curve, circle, ellipse, rectangle, fillet. Ortho constraint and close-to-start detection. A closed curve is smooth all the way round, with no kink where it closes. Ends dropped onto another piece offer to join it into one outline. A polyline is one shape, not a string of separate lines.
- Move, point to point or by the numbers. Tap a point on the selection and the spot it goes, snapping at both ends, or type how far to move in X and Y.
- Editing tools. Trim, an erase brush, offset, mirror, rotate, scale, copy and paste, group, align, distribute, divide lines or curves into equal segments, and undo and redo throughout. Join turns pieces that meet end to end into one outline and Explode splits an outline back into lines and arcs. One tool is armed at a time, so a waiting action never fires under the next one; tap its button again, or press Escape, to put it down.
- Corner or smooth, point by point. Convert switches any point of a polyline or curve between a sharp corner and a smooth curve with a tap, without moving it.
- True arcs that stay arcs. A fillet, a rounded corner or a fitted arc is stored as a real arc inside the outline, so trimming, offsetting, mirroring or moving a neighbouring point keeps it an arc with its radius. Fit Arc paints across any stretch of geometry, traced or drawn, and replaces it with the arc or smooth curve that fits.
- Exact offsets. Offset a traced outline and it comes back as a clean outline the given distance away, corners mitred or rounded, fillets offset as fillets, and any part that would fold back on itself trimmed away. It previews the moment you open it, with a flip for the other side.
- Edit points. Every vertex of a traced outline is a handle at any zoom. Drag one, tap to add one, hold to delete one, or brush over a run of points and move them together. A corner two outlines share moves as one, a fillet inside the outline stays a fillet with its own radius handle, and a near miss between points never drags the whole shape.
- Symmetry. Draw the line of symmetry across a traced part and tap the half to replace; the good half is mirrored over it. Labels in each half say which side you are about to keep.
- Dimensions and measure. Ortho, aligned, angle and radius dimensions, plus on-the-spot measurement of a distance, an angle, a radius, any single element, or the enclosed area of a closed shape. Radius dimensions follow the geometry, so standardizing a hole updates its label.
- Snap onto the geometry. Configurable snap levels: endpoints, centres, midpoints, quadrants and every vertex of a trace, plus points ON a line or curve between its vertices, the intersection of two shapes, the tangent point on a circle or curve, and the perpendicular foot from the last point placed.
- Tracking guides. Rest on a point for a moment to anchor it, and level, plumb and extension lines run from it while you draw or drag; where two of them cross is a point you can place on. A dragged point slides level or plumb with where it started.
- Smart contour fitting. Paint a brush stroke over the photo and LensCAD fits precise geometry to the edge beneath. The image processing finds the shape; the CAD engine creates the entity.
- Standardize. Group similar circles, rectangles or fillets and snap them all to the nearest standard size, 1/16 inch or 0.5 mm. Tap it again to round coarser, up to 1/2 inch or 5 mm.
- Snap corners and weld ends. Snap Corners extends nearby lines to meet at clean intersections. Weld Ends merges endpoints that are close but not touching. Together they turn a messy trace into a clean closed profile.
- Clean up. One button on a traced part: thin out crowded points without changing the shape, then weld the seams where two components share a real edge so they draw as one line.
- Paint to select, distribute, divide, total length. Drag a brush across geometry to select everything it touches. Distribute three or more objects with equal spacing. Split a line or curve into N equal segments with a live preview. Measure the total path length of any selection for cut lists and gaskets.
- Layers that are the part. A layer is the component name Smart Trace gave the shape, so renaming one renames it in CAD. Set each layer's colour and line weight, both carried into the DXF, or hide or lock it; hold the eye or the padlock to isolate one. Locked geometry draws grey and cannot be selected, moved or erased by accident. A 3D chip on each layer decides whether it goes into the 3D model, and holding it makes the layer an add-on part.
- Other views as reference. Show another view's geometry on this one, dashed: a view that shares one axis projects lines across, the opposite side is overlaid mirrored. Snaps and guides reach it, and it can be dragged into line with the part.
- Type a command. With a keyboard on a computer or an iPad, start typing a tool's name (Polyline, Move, Offset, Dim) or a short name like L or M and press Enter. Enter again repeats it.
- Numbers in any unit. A length box takes 25mm, 1/2", 13' 6" or a sum like 13x12, and converts it to the part's units.
A 1:1 DXF, with layers and dimensions.
Download a DXF at true scale, ready for any CAD program. Each named component is its own layer with its colour; dimensions land on their own layer. Curves go out as true splines, one smooth move for a CNC controller, or as points if you prefer. A multi-view part exports as a third-angle sheet or as 3D planes, every view lined up with the others by the part itself, with the option to crop each photo to the traced part. Every download carries a plain-text report: the photo's resolution as it was sent, the rectified scale, and how each Smart Trace run went. When something looks off, the answer is in the zip.
Save, reopen, import.
Save the whole part as a project file you keep: every view, all your geometry, dimensions, layers and colours, and the 3D model's cut, recess and boss settings. Open it again on any device and carry on where you left off. Included on the free tier. The File menu also imports a DXF from any CAD program, as a new part or onto the view you are drawing, with its layers, arcs and units kept.
Any error offers a Report button with the details already attached, and the help menu has one for anything else. Reports land in front of a person.