The Complete Guide to Blender Graphics

NURBS and Meta Shapes

11

11.1 Using NURBS

11.2 Creating a Lofted Tunnel

11.3 Meta Shapes

11.1 Using NURBS

When you press Shi + the A key and select “Add,” you will notice other object

types besides meshes, cameras, and lights that can be created. One other type of

object that can be created is a surface (NURBS). NURBS stands for Non-Uni-

form Rational B-Spline, which means it’s a type of editable curve or surface that

can be converted to a mesh object. If you look at the “Surface” menu, you will see

a variety of shapes that can be created. ese shapes can be used as they are or

converted to meshes so you can work with vertices. To get you started and give

you an idea of how this is achieved, follow the procedure outlined below.

Start a new scene in Blender and delete the default cube. Place the scene in

top view (number pad 7) and add a NURBS circle (Shi + the A key – “Add” –

“Surface” – “NURBS Circle”). e NURBS circle will be displayed in the scene

in object mode (Figure 11.1).

Tab to edit mode and you will see the circle surrounded by manipulation

handles, which by default are all selected (Figure 11.2). Deselect the handles

using the A key and right click on a handle to select it. If you have the manipu-

lation widget turned on, you can use it to move the handle and deform the

circle (Figure 11.3). Alternatively, you can press the G key and drag the mouse.

Tab into object mode to see the deformed circle (Figure 11.4). e defor-

mation may be what you want or you may wish to further rene the shape.

Figure 11.1

Figure 11.2

186 11. NURBS and Meta Shapes

You can do this by converting the NURBS shape

into a mesh object. With the shape selected in ob-

ject mode, press Alt + the C key and select “Mesh

from Curve/Meta/Surf/Text” in the drop down

menu (Figure 11.5). We are converting “Surf” into

a mesh object. Obviously this same command is ap-

plicable to converting “Curve,” “Meta,” and “Text”

into a mesh object.

Tab to edit mode and you will see the shape now

has vertices applied that you can select and manipu-

late to further modify the shape (Figure 11.6). e A

key will deselect the vertices you have just moved and

pressing the A key again will select all the vertices.

Tab to object mode then press Alt + the C key; this

time select “Curve from Mesh/Text” (Figure 11.7). is

option creates a mesh curve object from the mesh ob-

ject. Tab back to edit mode and you now have a curve

Figure 11.3

Figure 11.5

Figure 11.6

Figure 11.4

Manipulation widget

Vertices selected Vertices moved

Deformed circle

18711.2. Creating a Loed Tunnel

circle object. You can use the “Geometry” values in the properties window – “Object Data”

button to manipulate the object’s shape or select vertices and move them (Figure 11.8).

Since this is a curve circle, it can be used as a path in animation.

is procedure shows that by converting one type of object to another, you have dierent

options for shape manipulation.

11.2 Creating a Lofted Tunnel

is process will take several proles of a NURBS circle, which are all manipulated to dier-

ent proles, and connect them together to form a hollow object (tunnel).

First, create a NURBS circle as described in Section 11.1. e circle is entered in the

scene in object mode, so you need to tab into edit mode. Select the points and shape the

circle a bit. Aer shaping, go back into object mode and change your view so you are look-

ing down on the circle (number pad 7). Use Shi + the D key to duplicate the circle several

times and position them accordingly, then rotate your view so you can shi select each

circle. In edit mode, edit the shapes. Aer shaping the circles, exit edit mode and select all

the circles by RMB clicking on them while holding Shi. Join the circles together, pressing

Figure 11.7

Figure 11.8

Single vertex selected and moved