Smooth lane boundaries

This is the second short lesson, after Your first three lanes. One small habit: turn on Smooth Boundary before drawing a curving lane.

The toggle lives in the Lane creation panel and changes how boundaries are generated for the lanes you draw next. Existing lanes are not touched.

The same curving centerline drawn twice — once with Smooth Boundary off, once with it on.

1. Open the Lane panel

Press N for the Lane tool. The right-side panel opens. Find the SMOOTH BOUNDARY row — the default is Off:

2. Draw a curving lane with the toggle off

Leave the toggle at Off. Click on the canvas to drop centerline points along a curve, and press Enter to finish.

The boundaries are straight segments between consecutive points, so the lane comes out angular:

3. Switch the toggle on, draw the same lane again

Click On in the SMOOTH BOUNDARY row. Click a similar centerline somewhere else on the canvas and press Enter.

This time the boundaries are spline-fitted, so the lane curves smoothly:

Side by side, the difference is obvious. The centerlines are the same; only the boundary generation rule changed.

When to leave it off, when to turn it on

	Smooth = Off	Smooth = On
Looks	Angular, faceted	Curved
Best for	Straight lanes, intersection legs	Curved roads, ramps
Performance	Slightly cheaper	Slightly more geometry

You can flip the toggle as often as you like. Each new lane uses whatever value is set when you finish drawing it.

What you learned

• The Smooth Boundary toggle lives in the Lane creation panel and applies to the next lane you draw, not the selected lane.
• Centerline geometry is the same in both modes; only the boundary rendering differs.

What’s next

• Use the Lane tool — the rest of the panel (Center Line vs Boundary mode, Lane Width, Lane Color).
• Manage lane connections — the four connection slots in the Attribute Panel.