3ds Max 2012 Bible - Kelly L. Murdock [154]
Cross Section
The Cross Section button works just like the Cross Section modifier by creating splines that run from one cross-section shape to another. For example, imagine creating a baseball bat by positioning circular cross sections for each diameter change and connecting each cross section from one end to the other. All the cross sections need to be part of the same Editable Spline object, and then using the Cross Section button, you can click from one cross section to another. The cursor changes when the mouse is over a shape that can be used. When you're finished selecting cross-section shapes, you can right-click to exit Cross Section mode.
The type of vertex used to create the new splines that run between the different cross sections is the type specified in the New Vertex Type section at the top of the Geometry rollout.
Caution
Although the splines that connect the cross sections are positioned alongside the cross section shape, they are not connected. •
After the splines are created, you can use the Surface modifier to turn the splines into a 3D surface.
Auto Welding end points
To work with surfaces, you typically need a closed spline. When you enable the Automatic Welding option in the End Point Auto-Welding section and specify a Threshold, all end points within the threshold value are welded together, thus making a closed spline.
Insert
The Insert button adds vertices to a selected spline. Click the Insert button, and then click the spline to place the new vertex. At this point, you can reposition the new vertex and its attached segments—click again to set it in place. A single click adds a Corner type vertex, and a click-and-drag adds a Bézier type vertex.
After positioning the new vertex, you can add another vertex next to the first vertex by dragging the mouse and clicking. To add vertices to a different segment, right-click to release the currently selected segment, but stay in Insert mode. To exit Insert mode, right-click in the viewport again or click the Insert button to deselect it.
Tutorial: Working with cross sections to create a doorknob
You can work with cross sections in several ways. You can use the Cross Section feature for Editable Splines, the Cross Section modifier, or the Loft compound object. All these methods have advantages, but the first is probably the easiest and most forgiving method.
To create a simple doorknob using the Editable Spline Cross Section button, follow these steps:
1. Right-click any of the Snap toggle buttons on the main toolbar, and select Grid Points in the Grid and Snap Settings dialog box. Then click the Snap toggle button on the main toolbar (or press the S key) to enable grid snapping.
2. Select the Create⇒Shapes⇒Circle menu command, and drag from the center grid point in the Top viewport to create a small circle. Repeat this step to create two more circles: one the same size and one much larger.
3. Select the Create⇒Shapes⇒Rectangle menu command, and hold down the Ctrl key while dragging in the Top viewport to create a square that is smaller than the first circle. Repeat this step to create another square the same size. Aligning the squares is easier if you select the Center option in the Creation Method rollout.
4. Click the Select and Move (W) button on the main toolbar, and drag the shapes in the Left viewport upward in this order: square, square, small circle, large circle, small circle. Separate the squares by a distance equal to the width of a door, and spread the circles out to be the width of a doorknob.
5. Select the bottom-most square shape, and then right-click and select Convert To⇒Editable Spline in the pop-up quadmenu.
6. In the Geometry rollout, click the Attach button and then select the other shapes