Measure Angles on CAD Drawings

A focused viewer for exported 2D linework

The CAD drawing angle tool treats selectable LINE, LWPOLYLINE, POLYLINE, SVG line, polyline, and polygon segments as vectors. It reports selected entity IDs, endpoints, the smaller and larger angles, clockwise and counterclockwise direction, CAD-style north bearing, and source units when the DXF declares them. PDF is rendered as a visual page because a plotted PDF may be vector, raster, or a mixture.

SVG is sanitized before parsing and is never inserted as active document markup. The ASCII DXF parser is dynamically imported and has a 10,000-segment safety limit. Unsupported circles, arcs, paths, annotations, and curves are reported rather than silently converted; blocks, solids, 3D faces, binary DXF, and DWG are rejected.

Select exact exported entities

1. Open a supported export and read any skipped-entity warning.
2. Use the layer switches and Zoom to fit to isolate the required linework.
3. Enable endpoint, midpoint, or intersection snap feedback, then click the first and second line entities.
4. Inspect IDs and endpoints, choose decimal precision, and compare smaller, larger, directed, and bearing outputs.
5. Turn on slope interpretation only when roof-pitch notation is actually relevant; otherwise the CAD result remains angle-focused.
6. Export PNG or SVG markup, or preserve selected entity fields in CSV or JSON.

Entity snap and coordinate precision

• Endpoint and midpoint snaps use stored entity coordinates rather than stroke thickness.
• Intersection snap is computed only for finite supported segments; an infinite extension is not invented.
• Displayed decimal precision changes formatting, not the underlying coordinates.
• An export can round coordinates, flatten curves, omit constraints, or convert text and dimensions to graphics.
• A PDF plotted from CAD can be rasterized, so it is treated as a background unless exact coordinate lines are entered.

Export review examples

• DXF fabrication handoff: isolate the CUT layer and compare two LINE entity bearings.
• SVG schematic: select two sanitized polyline segments and export their IDs and endpoints.
• Rasterized PDF detail: use the page as visual context and add authoritative coordinate lines supplied with the drawing.
• Slope review: explicitly enable slope interpretation for one roof edge; leave it off for machine or layout angles.

Supported and rejected CAD data

ASCII DXF LINE plus open or closed LWPOLYLINE and 2D POLYLINE are the tested subset. DXF units are shown when $INSUNITS uses a recognized code. SVG support is intentionally limited to safe straight linework. PDF pages provide context but are not claimed as vector entities.

• Supported: SVG line/polyline/polygon, PDF page background, ASCII DXF LINE/LWPOLYLINE/POLYLINE.
• Reported as skipped: unsupported 2D shapes such as circles, arcs, paths, hatches, and text.
• Rejected: active SVG, external SVG resources, binary DXF, blocks/INSERT, 3D entities, DWG, and files above the segment limit.

Not a DWG editor or engineering certification tool

This is a bounded 2D export reader, not a native CAD model editor. It does not open DWG, execute scripts, expand blocks, resolve constraints, approximate unsupported curves, inspect 3D geometry, or certify engineering work. Confirm exact design intent in the original CAD system and controlled revision.

Parsing and rendering occur locally. SVG active content and external references are rejected, and the drawing is not uploaded.