How to Draw Polylines in BricsCAD

Quick answer: A polyline is an open or closed sequence of connected line and/or arc segments, all treated as a single entity, unlike a series of separate LINE segments. Each segment can have a constant or tapered width. Beyond drawing one interactively with PLINE, you can also create one from an enclosed area with BOUNDARY, or from a series of already-drawn entities with JOIN.

What a Polyline Is

Every segment stays part of one continuous entity, which is what makes a polyline different from drawing the same shape with individual LINE segments. Find the Polyline tool on the Draw menu, the Draw toolbar, the Draw ribbon panel, or the Draw tab of the No Selection Quad.

Thickness and Elevation

Don’t confuse these with segment width, they’re separate properties entirely:

• Thickness: the height of a polyline, essentially a 3D extrusion. At 0 (the default, saved via THICKNESS), there’s no visual difference between a polyline and a plain series of lines and arcs.
• Elevation: the distance between the polyline’s own plane and the WCS’s XY-plane.

Segment width is separate again, and can be zero, constant, or tapered along a segment’s length.

Editing and Direction

You can modify a polyline as a whole, or edit individual segments and add or remove vertices. The GRIPS system variable controls which points show grips: at 1, just endpoints and vertices; at 2, also the midpoints of each vertex.

Polylines also have a direction, which affects things like tapered widths, reversible via the Reverse Direction option of PEDIT.

One more thing worth knowing: with FILLMODE set to 0, wide polylines display as outlines only, the same behaviour covered on the Fill Mode page.

Drawing a Polyline: General Procedure

1. Launch PLINE. You’re prompted for the start of the polyline.
2. Specify a point. You’re prompted for the next point, or to choose an arc, distance, follow, halfwidth, or width option.
3. Specify another point. The same options are available, plus Undo now.
4. Specify another point. Close becomes available too at this stage.
5. Keep specifying points as needed.
6. Either choose Close to connect back to the start and finish a closed polyline, Undo to remove the last vertex, or press Enter or right-click to stop.

Creating Boundary Polylines

1. Launch BOUNDARY. The Boundary dialog opens.
2. Click Pick points in boundaries. The dialog closes.
3. Click inside the area you want bounded. The resulting boundary polyline highlights.
4. Optionally keep picking points to create more boundary polylines.
5. Right-click to accept. The Boundary dialog reopens.
6. Click OK. The polyline(s) are created.

Joining Entities into a Polyline

JOIN combines a series of connected lines, polylines, and arcs into a single polyline, an alternative to drawing one from scratch when the individual pieces already exist.

Frequently Asked Questions

Is a polyline one entity or several separate ones? One. Every segment stays part of the same entity, unlike drawing the same shape with individual LINE segments.

What’s the difference between a polyline’s Thickness and its segment width? Thickness is a 3D extrusion height, essentially how tall the polyline stands. Segment width is a separate, flat property, which can be constant or tapered along each segment.

How do I turn a series of existing lines and arcs into one polyline? Run JOIN on them, provided they’re already connected at their endpoints.

Can I reverse which end of a polyline is considered the start? Yes, use the Reverse Direction option of PEDIT.