Interactions Between Curves

Maya contains several operations that are based on the relationships between pre-existing curves. The Offset and 2d Fillet functions are perhaps the most common of these.

Creating a new curve that parallels an existing one (like a spiral ramp, or a rounded edge) can be difficult if the original curve has complicated or spiral topology. The Offset Curve function creates a copy of your curve a fixed distance from the original at all points (Figure 7.49).

Figure 7.49. This spiral was created easily by curling a curve and then offsetting it to create the second curve needed to loft a surface.

To offset a curve:

1.	Select a curve, choose Edit Curves > Offset, and click the option box next to Offset Curve (Figure 7.50). Figure 7.50. Select Edit Curves > Offset, and select the box next to Offset Curve. The Offset Curve Options dialog box opens.
2.	Set the Offset Distance to 2 (Figure 7.51). Figure 7.51. Enter 2 in the Offset Distance box.
3.	Click Offset. A new curve is created that is exactly 2 units from the original (Figure 7.52). Figure 7.52. The new curve is 2 units away in all perpendicular locations. Note that this is different than duplicating and scaling a curve.

Like many functions in Maya, you can scale the distance interactively using the Channel Box. To do so, select the input node, and change the value until the new curve is the desired distance away from the source curve (Figure 7.53).

Figure 7.53. Using the Channel Box, you can adjust the distance of the existing offset easily rather than performing the operation again.