By Jonathan Block

About This Arm

This arm was created as part of a creature I was modeling, it doesn't have fewer fingers out of laziness. Few modifications are required to increase the number of digits.

About Object Snaps

Many of the commands rely on object snaps for accuracy. Open the Osnap dialog box and position it in your workspace.

To open the Osnap dialog box:

• On the status bar, click Osnap.

Define the Shape of the Arm

You will draw four curves representing the top and bottom and sides of the arm. Then you will draw cross-section curves through the profile curves and loft the cross section curves.

To draw the profile curves:

1. From the View menu, click 4 Viewports.

2. From the Curve menu, click Free-form, and then click Interpolate Points.

3. In the Front viewport, draw the top and bottom shapes of the arm from the shoulder to the wrist.

   
   Draw a profile of the top and bottom of the arm in the Front viewport.

4. From the Curve menu, click Free-form and then click Interpolate Points.

5. In the Top viewport, draw the front and back shapes of the arm emphasizing the biceps and elbow.

   
   Draw a profile of the front and back of the arm in the Top viewport.

6. From the Transform menu, click Move and align the curves with the other curves as shown in the previous two pictures

Create the Cross Section Curves for the Arm

Cross-section curves will be used to define the loft surface.

To draw the cross-section curves:

1. From the Curve menu, click CSec Profiles.

2. At the Select curves in order prompt, choose the curves in the order shown (bottom, front, top, back).

   
   Select the profile curves in order.

3. In the Front viewport, draw lines at approximately right angles to the arm shape curves. Make sure the lines cross ALL arm shape curves.

   
   Draw the cross section curves in the Front viewport.

4. From the Curve menu, click Free-form, and then click Interpolate points.

5. Draw curves at each end of the arm shape curves.

6. Use object snaps to snap to the ends in the order picked for the CSec Profiles (bottom, front, top, back), and type C to close the curve.

   
   Draw curves for the end of the arm.

Loft the Arm

Lofting creates a surface through curves.

To loft the cross-section curves:

1. Select all the arm curves.

2. From the Surface menu, click Loft.

3. In the Loft Options dialog box, use the Rebuild with control points option to set the number of control points to 8.

   
   Loft the arm curves.