Curve objects — ModelCraft help

A curve object is a curve that makes a shape: a tube along it (bevel), a band (extrude), a tapering horn (taper), or — when it is flat and closed — a filled plate or letters. The shape follows the curve: move a point and the tube moves with it. When the shape is right, turn it into a mesh.

Add a curve

Pick Curve in the Workspace list and press Add:

Kind	What it is
Bézier curve, Bézier circle	Passes through its points; each point has two handles that set the curve's direction
NURBS curve, NURBS circle, Path	Smooth, drawn towards its points (it starts and ends on its end points); each point has a weight
Text	Your text as flat, filled letter outlines

A new curve gets a thin tube so it can be seen and picked; set its bevel depth to 0 for a bare curve.

You can also start from something drawn: select an arc, a circle, a polygon or a drawn curve in the Model workspace and press Make a curve object in Entity info. The drawn lines stay.

Edit the points

Double-click a curve object (or select it and pick Curve) to edit it.

Click a point or handle (Shift adds or removes); drag it to move it. Drag on empty space to select with a box.
Extend (EE, or ⌃Ctrl+click) adds a point after the selected end, at the pointer.
Subdivide (WW) puts a point between each pair of selected neighbours; a Bézier keeps its shape.
Move, Turn, Scale move the selected points with the pointer (modeler keys GG RR SS, push/pull keys MM QQ SS); click to keep, EscEsc to cancel.
Close (CC) closes an open spline or opens a closed one; Reverse (⇧RShift+R) runs it the other way.
Bézier handles: Smooth (VV) places them for a smooth curve, Corner (⇧VShift+V) points them at the neighbours, Free (⌥VAlt+V) leaves them where you put them. Dragging a handle makes it free.
Bézier, NURBS and Poly change the selected splines' type, keeping the points.

Every change is one undo step.

Shape

The settings are in the panel (and in Entity info in the Model workspace):

Shape: 3D curves go any way; a flat curve stays in its own plane and can be filled.
Fill closed splines (flat): the outlines become a plate; an outline inside another is a hole, so letters keep their holes.
Extrude: half the band's width (open or 3D curves), or half the plate's thickness (filled).
Bevel depth and roundness: a round tube along the curve (with extrude: a rounded band); on a filled shape, a rounded edge.
Close the ends: caps on an open tube.
Taper along it: scales evenly along each spline, for example 1, 0.2 for a horn, 0, 1, 0 for a spindle.
Smoothness and, for NURBS, order: how finely it is drawn, and how smooth (2 straight … 6 smoothest).
With points selected: radius (the tube's thickness there, times the bevel), tilt (turns the band about the curve) and, for NURBS, weight.

Modifiers work on top of a curve object as on a mesh: an Array along it, a Mirror, a Subdivision surface. See Modifiers on a mesh.

Turn it into a mesh

To mesh (in the Curve workspace or in Entity info, Curve to mesh) makes the curve object the mesh it shows now; its modifiers stay on top. Then edit it in the Mesh workspace. Undo turns it back.