Editing a volume

Select a volume, then work directly in the viewport:

Action	Result
Drag a point handle	Move that point
Shift + Click points	Select multiple points (drag or delete them together)
Click the line	Insert a point there (inherits smoothing from its neighbours)
Select an end point, then Ctrl + Click	Extend the line from that end
Delete	Remove the selected points (minimum of 2 kept)
Right-click a point	Set its smoothing mode

Point smoothing

Each point can interpolate differently, so one spline can mix hard corners and smooth curves:

Mode	Behaviour
Linear	Straight corner. The default.
Catmull-Rom	Smooth curve, tangents derived from the neighbours.
Bezier	Smooth curve with a mirrored tangent handle you drag.

The point's colour shows its mode at a glance; an L / C / B letter appears next to the hovered or selected point. Modes can also be set from the Spline Point section of the panel, and apply to a whole multi-selection.

Shape settings

Setting	Effect
Width	Band width around the drawn line
Offset Mode	Band sits Center / Inner / Outer relative to the line
Height, Z Offset	Extrusion height and base offset
Closed	Connect the last point back to the first
Fill Area	Closed only: fill the enclosed area instead of building a band
Flatten to Base	On: flat base at the lowest point. Off: base follows each point's height

Corners keep an even width through miters, and sharp corners bevel instead of spiking. Self-intersecting outlines are resolved automatically so overlapping areas do not double up.

WARNING

Closed rings around very tight curves can still self-overlap — see Known limitations.