3ds Max 2012 Bible - Kelly L. Murdock [164]
FIGURE 12.37
The Shape Check utility can identify spline intersections.
Extruding splines
Because splines are drawn in a 2D plane, they already include two of the three dimensions. By adding a Height value to the shape, you can create a simple 3D object. The process of adding Height to a shape is called extruding.
To extrude a shape, you need to apply the Extrude modifier. To do so, select a spline object and choose Modifiers⇒Mesh Editing⇒Extrude, or select the Extrude modifier from the Modifier Stack drop-down list. In the Parameters rollout, you can specify an Amount, which is the height value of the extrusion; the number of Segments; and the Capping options (caps fill in the surface at each end of the Extruded shape). You can also specify the final Output to be a Patch, Mesh, or NURBS object. Figure 12.38 shows capital Es that model the various vertex types extruded to a depth of 10.0.
FIGURE 12.38
Extruding simple shapes adds depth to the spline.
Tutorial: Routing a custom shelf
In Woodshop 101, you use a router to add a designer edge to doorframes, window frames, and shelving of all sorts. In Woodshop 3D, the Boolean tools work nicely as you customize a bookshelf.
To create a custom bookshelf using spline Boolean operations, follow these steps:
1. Open the Bookshelf.max file from the Chap 12 directory on the CD.
This file includes a triangle shape drawn with the Line primitive that is overlapped by three circles. All these shapes have been converted and combined into a single Editable Spline object.
2. Select the shape, open the Modify panel, and select the Spline subobject mode (or press the 3 key) and select the triangle shape.
3. Select the Subtraction Boolean operation (the middle icon) in the Geometry rollout, and click the Boolean button. Then select each of the circles and right-click to exit Boolean mode. Then click Spline in the Modifier Stack again to exit subobject mode.
4. Back in the Modify panel, select the Extrude modifier from the Modifier drop-down list and enter an Amount of 1000. Select Zoom Extents All to resize your viewports, switch to the Perspective viewport, and view your bookshelf.
Figure 12.39 shows the finished bookshelf in the Perspective viewport ready to hang on the wall.
FIGURE 12.39
The finished bookshelf created with spline Boolean operations and the Extrude modifier
Lathing splines
Another useful modifier for 2D splines is the Lathe. This modifier rotates the spline about an axis to create an object with a circular cross section (such as a baseball bat). In the Parameters rollout, you can specify the Degrees to rotate (a value of 360 makes a full rotation) and Cappings, which add ends to the resulting mesh. Additional options include Weld Core, which causes all vertices at the center of the lathe to be welded together, and Flip Normals, which realigns all the normals.
The Direction option determines the axis about which the rotation takes place. The rotation takes place about the object's pivot point.
Caution
If your shape is created in the Top view, then lathing about the screen Z-axis produces a thin disc without any depth. •
Tutorial: Lathing a crucible
As an example of the Lathe modifier, you create a simple crucible, although you could produce any object that has a circular cross section. A crucible is a thick porcelain cup used to melt chemicals. I chose this as an example because it is simple (and saying “crucible” sounds much more scientific than “cup”).
To create a crucible using the Lathe modifier, follow these steps:
1. Open the Crucible.max file from the Chap 12 directory on the CD.
This file includes a rough profile cross-section line of the crucible that has been converted to an Editable Spline.
2. Select the line, and select the Modifiers⇒Patch/Spline Editing