Blender 3D: Noob to Pro/Curves In 3d
|Applicable Blender version: 2.49.|
Bezier Curves in 3d 
In the previous page, we learned how to create and basically manipulate Bézier curves in two dimensions, as well as extruding them into the third. Here we will be exploring the '3D' button you may have been wondering about in the 'Curve and Surface' menu and some of its implications.
- Create a basic curve: Press 'SPACE - Add - Curve - Bézier Curve' in case you have forgotten.
If you have been playing around with the control points on any curves so far, you will have noticed that they cannot be moved outside the flat plane made up by the X and Y axes. This is because it hasn't been enabled yet, so go ahead and enable it...
- Enabling 3D editing: Locate and press the button labelled '3D' in the 'Curve and Surface' menu.
Your curve should now look like this in Edit Mode:
Our previously simple curve has now been covered with arrows! These indicate the direction of the curve, and also the normal size and tilt. But more of that later...
Getting started in 3D 
Editing the curve should now be child's play, assuming you have already completed the tutorials on 3d meshes.
- Rotate the camera view: Use the MMB or some Numpad keys to rotate the view so you can see the 3d axes.
- Move a point: Select one of the control points (NB: A point, not a handle) and move it with GKEY. You may want to constrain its motion to the new Z axis using ZKEY twice.
If you rotate around the curve, you can see how the interpolation works in three dimensions, and that the arrows still follow its direction correctly. It is worth noting that they are all mostly vertically (for the moment at least), this will be discussed in the next section.
Extruding revisited 
I'm sure you will be delighted to learn that we can still use the Extrude option on 3d curves! Try cranking up the value, and you will see a surface created through your curve, at right angles to the 'normal' arrows.
The Bevel settings will also work as before, but you probably don't need to use them unless you are editing a 'filled' curve (CKEY).
Also, The Subdivided option(W, 1) still applies while working with curves. Just select two(or more) handles of the curve that are right next to each other, and subdivide. You should have a newly created handle(s) in between the handles you selected to subdivide.
Bevel Objects 
(Information on bevel objects to come...)
Curve Tilting and Normal-scaling 
Use TKEY to tilt the curve, clockwise or counterclockwise (looking along the line of the curve). For Blender version: 2.6x use Ctrl+T to tilt. Use Alt-SKEY to scale the curve, making it wider or narrower.
Convert Curve to Mesh 
Use Alt+C [ObjectMode>Menu>Object>Convert to>Mesh from...].
Shape typ 2D = mesh with auto add faces and edges Shape typ 3D = mesh only edges and vertex
(To be expanded...)