Creating a ShapeMerge Object

The ShapeMerge compound object enables you to use a spline shape as a cookie cutter to extract a portion of a mesh object. This button is enabled only if a mesh object and a spline exist in the scene. To use this object, select a mesh object and click the Pick Shape button in the Pick Operand rollout, and then select a spline shape. The shape can be a Reference, Move, Instance, or Copy.

The spline shape is always projected toward its negative Z-axis. By rotating and positioning the spline before selecting it, you can apply it to different sides of an object. You can apply multiple shapes to the same mesh object.

The Parameters rollout, shown in Figure 18.5, displays each mesh and shape object in a list. You can also rename either object using the Name field. The Extract Operand button lets you separate either object as an Instance or a Copy.

Figure 18.5: Use the Parameters rollout for the ShapeMerge compound object to cut or merge a shape

Cookie Cutter and Merge options

The Operations group includes options for cutting the mesh, including Cookie Cutter and Merge. The Cookie Cutter option cuts the shape out of the mesh surface, and the Merge option combines the spline with the mesh. You can also Invert the operation to remove the inside or outside of the selected area.

Like the Boolean Subtraction operations, the Cookie Cutter option can remove sections of the mesh, but it uses the area defined by a spline instead of a volume defined by a mesh object. The Merge option is useful for marking an area for selection. Figure 18.6 shows a ShapeMerge object with the Cookie Cutter option selected.

Figure 18.6: A ShapeMerge object using the Cookie Cutter option

Note 

You can use the Merge option to create a precise face object that can be used with the Connect object.

The Output Sub-Mesh Selection option lets you pass the selection up the Stack for additional modifiers. Options include None, Face, Edge, and Vertex.

Note 

To see the backsides of the faces, right-click the object, select Properties from the pop-up menu, and disable the Backface Cull option.

Tutorial: Using the ShapeMerge compound object

When outlined text is imported into Max, it typically contains letters that have shapes within shapes. For example, the letter p, when outlined, includes the outline of the letter p and a circle shape to denote the interior section of the letter. When outline text like this is converted to a mesh object, both the letter outline and its interior section are covered, making the text illegible. You can use the ShapeMerge compound object to remedy this tricky situation.

You can practice handling this situation using the logo for the fictional Box It Up company. Before this logo can be extruded, you need to do some work involving the ShapeMerge object.

To use the ShapeMerge object to remove the center area from an extrusion, follow these steps:

1. Open the  Box It Up Co logo.max file from the Chap 18 directory on the DVD.

2. Select all the letters in the logo, press the Ctrl key, and deselect the interior shapes in the B, O, and P letters. Then apply the Extrude modifier with an Amount value of 0.010 feet.

3. Select the letter B shape again. Then select the Create Compound ShapeMerge menu command.

4. Set the Operation to Cookie Cutter, and click the Pick Shape button in the Pick Operand rollout with the Copy option. Select the two interior shapes for the letter B. Then click the Select Object button on the main toolbar again to exit ShapeMerge mode. Then repeat this step for the letters O and P.

Figure 18.7 shows the finished logo. Notice that the letters have the interior sections removed.

Figure 18.7: The logo with the interior centers removed from extruded letters using the ShapeMerge object