Nurbs Basics

Tutorial written by Tom.Klejne for http://www.3dspline.com. (For any questions, feel free to contact me)

In this tutorial I will show you the very basics of NURBS in creating a simple baseball bat. This tutorial teaches u-loft and cap NURBS surface creation. NURBS has many advantages over creating this using lathe, one of them is that after you have a NURBS baseball bat you can create many different baseball bats by just scaling and moving these circles, another advantage would be with animation.

1. Turn the 2d or 3d snap

on, to make it easier to work with, click create then shape then circle, and in the top viewport create a circle like the one in fig 1.1, this will be the very tip of your bat.

Figure 1.1

2. In the front viewport, while holding down the shift key move the circle down a bit. When the clone options dialog comes up, select copy and click OK, now scale the bottom circle out a bit as shown in figure 1.2

Figure 1.2

3. Repeat This process until you get the circles to form a baseball bat, as shown in figure 1.3 (note. The circles do not need to look perfect yet, its better to perfect it later in real time when the surface is already applied)

Figure 1.3

4. Now its time to turn these splines into NURBS!. Select the first circle, click modify then click "edit stack" and select NURBS from the drop down menu, this will convert that circle into NURBS (Note. If you have other modifier applied before converting into NURBS you'll need to collapse the stack by clicking the collapse button.).

Important note: when working with NURBS its best to have "force 2-sided" turned on, unless you want to be flipping normals on every 2nd surface, right click Perspective text, select configure and turn on "force 2-sided".

5. Click and attach all the circles in any order, this is needed in order to do any surfacing with NURBS Still in the NURBS modify panel, open up the surface rollout, click cap and select the first circle (the small one at the top of the bat). This should create a flat surface over that circle as shown in figure 1.4

Figure 1.4

6. Here comes the real surface, still in the surface rollout click u-loft then click on the top circle, then 2nd from top, then 3rd from top, and right click to stop the u-loft process there. This should now look like figure 1.5

Figure 1.5

7. Now zoom out and do the same For the 3rd, 4th, and 5th circles, and again right click to stop right there, and it should look like figure 1.6. The reason behind not doing this in 1 swift u-loft is because u-loft works that it fits a smooth surface along the u-loft For a more organic look, there fore sharp corners can distort the whole u-loft surface.

Figure 1.6

8. By now you should understand how u-loft and cap work, so finish off the model by u-lofting the rest of the shapes, and putting a cap on the bottom circle, and the finally result should look like figure 1.7. If it doesn't look right, here is how you modify every step you used in creating it in real time... Still with the object selected in the modify NURBS rollout, click sub-object and select curves

, here you can select each curve and scale/move it any way you like and the surface will automatically be updated.

You just created a baseball bat! not only a baseball bat but a NURBS baseball bat :).

Figure 1.7