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13_381304-ch08.qxp 7/7/08 3:02 PM Page 219 Cloning Objects and Creating Object Arrays T he only thing better than one perfect object is two perfect objects. Cloning objects is the process of creating copies of objects. These copies can maintain an internal connection (called an instance or a reference) to the original object that allows them to be modified along with the original object. For example, if you create a school desk and clone it multiple times as an instance to fill a room, then changing the parameter of one of the desks automatically changes it for all the other desks also. An array is a discrete set of regularly ordered objects. So creating an array of objects involves cloning several copies of an object in a pattern, such as in rows and columns or in a circle. I’m sure you have the concept for that perfect object in your little bag of tricks, and this chapter lets you copy it over and over after you get it out. IN THIS CHAPTER Cloning objects Understanding copies, instances, and references Using the Mirror and Snapshot tools Spacing clones along a path with the Spacing tool Using the Clone and Align tool Creating object arrays Cloning Objects Using the Ring Array system You can clone objects in Max in a couple of ways (and cloning luckily has nothing to do with DNA or gene splices). One method is to use the Edit ➪ Clone (Ctrl+V) menu command, and another method is to transform an object while holding down the Shift key. You won’t need to worry about these clones attacking anyone (unlike Star Wars: Episode II). Using the Clone command You can create a duplicate object by choosing the Edit ➪ Clone (Ctrl+V) menu command. You must select an object before the Clone command becomes active, and you must not be in a Create mode. Selecting this command opens the Clone Options dialog box, shown in Figure 8.1, where you can give the clone a name and specify it as a Copy, Instance, or Reference. You can also copy any controllers associated with the object as a Copy or an Instance. 219 13_381304-ch08.qxp Part II 7/7/08 3:02 PM Page 220 Working with Objects The Edit menu doesn’t include the common Windows cut, copy, and paste commands because many objects and subobjects cannot be easily pasted into a different place. However, you will find a Clone (Ctrl+V) command, which can duplicate a selected object. CAUTION FIGURE 8.1 The Clone Options dialog box defines the new object as a Copy, Instance, or Reference. CROSS-REF The difference between Copy, Instance, and Reference is discussed in the “Understanding Cloning Options” section in this chapter. When a clone is created with the Clone menu, it is positioned directly on top of the original, which makes distinguishing it from the original difficult. To verify that a clone has been created, open the Select by Name dialog box by pressing H and look for the cloned object (it has the same name, but an incremented number has been added). To see both objects, click the Select and Move button on the main toolbar and move one of the objects away from the other. Using the Shift-clone method An easier way to create clones is with the Shift key. You can use the Shift key when objects are transformed using the Select and Move, Select and Rotate, and Select and Scale commands. Holding down the Shift key while you use any of these commands on an object clones the object and opens the Clone Options dialog box. This Clone Options dialog box is identical to the dialog box previously shown, except it includes a spinner to specify the number of copies. Performing a transformation with the Shift key held down defines an offset that is applied repeatedly to each copy. For example, holding down the Shift key while moving an object five units to the left (with the Number of Copies set to 5) places the first cloned object five units away from the original, the second cloned object ten units away from the original object, and so on. Tutorial: Cloning dinosaurs The story behind Jurassic Park is pretty exciting, but in Max you can clone dinosaurs without their DNA. To investigate cloning objects, follow these steps: 1. Open the Cloning dinosaurs.max file found in the Chap 08 directory of the DVD. 2. Select the dinosaur object by clicking it in one of the viewports. 3. With the dinosaur model selected, choose Edit ➪ Clone (or press Ctrl+V). The Clone Options dialog box appears. 220 13_381304-ch08.qxp 7/7/08 3:02 PM Page 221 Cloning Objects and Creating Object Arrays 4. Name the clone First clone, select the Copy option, and click OK. 5. Click the Select and Move button (or press the W key) on the main toolbar. Then in the Top viewport, click and drag the dinosaur model to the right. As you move the model, the original model beneath it is revealed. 6. Select each model in turn, and notice the name change in the Create panel’s Name field. Notice that the clone is even the same object color as the original. 7. With the Select and Move button still active, hold down the Shift key, click the cloned dinosaur in the Top viewport, and move it to the right again. In the Clone Options dialog box that appears, select the Copy option, set the Number of Copies to 3, and click OK. 8. Click the Zoom Extents All button (or press Shift+Ctrl+Z) in the lower-right corner to view all the new dinosaurs. Three additional dinosaurs have appeared, equally spaced from each other. The spacing was determined by the distance that you moved the second clone before releasing the mouse. Figure 8.2 shows the results of our dinosaur cloning experiment. (Now you’ll need to build a really strong fence.) FIGURE 8.2 Cloning multiple objects is easy with the Shift-clone feature. 221 8 13_381304-ch08.qxp Part II 7/7/08 3:02 PM Page 222 Working with Objects Understanding Cloning Options When cloning in Max, you’re offered the option to create the clone as a copy, an instance, or a reference. This is true not only for objects, but for materials, modifiers, and controllers as well. Working with copies, instances, and references When an object is cloned, the Clone Options dialog box appears. This dialog box enables you to select to make a copy, an instance, or a reference of the original object. Each of these clone types is unique and offers different capabilities. A copy is just what it sounds like — an exact replica of the original object. The new copy maintains no ties to the original object and is a unique object in its own right. Any changes to the copy do not affect the original object, and vice versa. Instances are different from copies in that they maintain strong ties to the original object. All instances of an object are interconnected, so that any geometry modifications (done with modifiers or object parameters) to any single instance changes all instances. For example, if you create several instances of a mailbox and then use a modifier on one of them, all instances are also modified. NOTE Instances and references can have different object colors, materials, transformations (moving, rotating, or scaling), and object properties. References are objects that inherit modifier changes from their parent objects, but do not affect the parent when modified. Referenced objects get all the modifiers applied to the parent and can have their own modifiers as well. For example, suppose that you have an apple object and a whole bunch of references to that apple. Applying a modifier to the base apple changes all the remaining apples, but you can also apply a modifier to any of the references without affecting the rest of the bunch. CROSS-REF Instances and references are tied to the applied object modifiers, which are covered in more detail in Chapter 11, “Introducing Modifiers and Using the Modifier Stack.” At any time, you can break the tie between objects with the Make Unique button in the Modifier Stack. The Views ➪ Show Dependencies command shows in magenta any objects that are instanced or referenced when the Modify panel is opened. This means that you can easily see which objects are instanced or referenced from the current selection. Tutorial: Creating instanced doughnuts Learning how the different clone options work will save you lots of future modifications. To investigate these options, you’ll take a quick trip to the local doughnut shop. To clone some doughnuts, follow these steps: 1. Create a doughnut using the Torus primitive by selecting Create ➪ Standard Primitives ➪ Torus, and then dragging and clicking twice in the Top viewport to create a torus object. 2. Click the torus object in the Top viewport to select it. 3. With the doughnut model selected, click the Select and Move button (or press the W key). Hold down the Shift key, and in the Top viewport, move the doughnut upward. In the Clone Options dialog box, select the Instance option, set the Number of Copies to 5, and click OK. Click the Zoom Extents All (or press the Shift+Ctrl+Z key) button to widen your view. 222 13_381304-ch08.qxp 7/7/08 3:02 PM Page 223 Cloning Objects and Creating Object Arrays 4. Select all objects with the Edit ➪ Select All (Ctrl+A) command, and then Shift+drag the doughnuts in the Top viewport to the right. In the Clone Options dialog box, select the Instance option again and 3 for the Number of Copies and click OK. This creates a nice array of two dozen doughnuts. Click the Zoom Extents All button (or press the Ctrl+Shift+Z key) to see all the doughnuts. 5. Select a single doughnut, and in the Parameters rollout of the Modify panel, set Radius1 to 20 and Radius2 to 10. This makes a nice doughnut and changes all doughnuts at once. 6. Select the Modifiers ➪ Parametric Deformers ➪ Bend command. Then in the Parameters rollout of the Command Panel, enter 25 in the Angle field and select the X Bend Axis. This adds a slight bend to the doughnuts. CROSS-REF You can use modifiers to alter geometry. You can learn about using modifiers in Chapter 11, “Introducing Modifiers and Using the Modifier Stack.” Figure 8.3 shows the doughnuts all changed exactly the same. You can imagine the amount of time it would take to change each doughnut individually. Using instances made these changes easy. FIGURE 8.3 Two dozen doughnut instances ready for glaze 223 8 13_381304-ch08.qxp Part II 7/7/08 3:02 PM Page 224 Working with Objects Tutorial: Working with referenced apples Now that you have filled our bellies with doughnuts, you need some healthful food for balance. What better way to add balance than to have an apple or two to keep the doctor away? To create some apples using referenced clones, follow these steps: 1. Open the Referenced Apples.max file from the Chap 08 directory on the DVD. 2. Select the apple, and Shift+drag with the Select and Move (W) tool in the Top viewport to create a cloned reference. Select the Reference option in the Clone Options dialog box. Then close the Clone Options dialog box. 3. Select the original apple again, and repeat Step 2 until several referenced apples surround the original apple. 4. Select the original apple in the middle again, and choose the Modifiers ➪ Subdivision Surfaces ➪ MeshSmooth command. In the Subdivision Amount rollout, set the number of Iterations to 2. This smoothes all the apples. 5. Select one of the surrounding apples, and apply the Modifiers ➪ Parametric Deformers ➪ Taper command. Set the Amount value to 0.5 about the Z-axis. 6. Select another of the surrounding apples, and apply the Modifiers ➪ Parametric Deformers ➪ Squeeze command. Set the Axial Bulge Amount value to 0.3. 7. Select another of the surrounding apples, and apply the Modifiers ➪ Parametric Deformers ➪ Squeeze command. Set the Radial Squeeze Amount value to 0.2. 8. Select another of the surrounding apples, and apply the Modifiers ➪ Parametric Deformers ➪ Bend command. Set the Angle value to 20 about the Z axis. As you apply modifiers to a referenced object, notice the thick gray bar in the Modifier Stack. This bar, called the Derived Object Line, separates which modifiers get applied to all referenced objects (below the line) and which modifiers get applied to only the selected object (above the line). If you drag a modifier from above the gray bar to below the gray bar, then that modifier is applied to all references. NOTE Using referenced objects, you can apply the major changes to similar objects, but still make minor changes to objects to make them a little different. Figure 8.4 shows the apples. Notice that they are not all exactly the same. 224 13_381304-ch08.qxp 7/7/08 3:02 PM Page 225 Cloning Objects and Creating Object Arrays FIGURE 8.4 Even apples from the same tree should be slightly different. Mirroring Objects Have you ever held the edge of a mirror up to your face to see half of your head in the mirror? Many objects have a natural symmetry that you can exploit to require that only half an object be modeled. The human face is a good example. You can clone symmetrical parts using the Mirror command. Using the Mirror command The Mirror command creates a clone (or No Clone if you so choose) of the selected object about the current coordinate system. To open the Mirror dialog box, shown in Figure 8.5, choose Tools ➪ Mirror, or click the Mirror button located on the main toolbar. You can access the Mirror dialog box only if an object is selected. Within the Mirror dialog box, you can specify an axis or plane about which to mirror the selected object. You can also define an Offset value. As with the other clone commands, you can specify whether the clone is to be a Copy, an Instance, or a Reference, or you can choose No Clone, which flips the object around the axis you specify. The dialog box also lets you mirror IK (inverse kinematics) Limits, which reduces the number of IK parameters that need to be set. CROSS-REF Learn more about inverse kinematics in Chapter 41, “Working with Inverse Kinematics.” 225 8 13_381304-ch08.qxp Part II 7/7/08 3:02 PM Page 226 Working with Objects FIGURE 8.5 The Mirror dialog box can create an inverted clone of an object. Tutorial: Mirroring a robot’s leg Many characters have symmetry that you can use to your advantage, but to use symmetry, you can’t just clone one half. Consider the position of a character’s right ear relative to its right eye. If you clone the ear, then the position of each ear will be identical, with the ear to the right of the eye, which would make for a strange looking creature. What you need to use is the Mirror command, which clones the object and rotates it about a selected axis. In this example, you have a complex mechanical robot with one of its legs created. Using Mirror, you can quickly clone and position its second leg. To mirror a robot’s leg, follow these steps: 1. Open the Robot mech.max file from the Chap 08 directory on the DVD. This file includes a robot with one of its legs deleted. 2. Select all objects that make up the robot’s leg in the Left viewport, and open the Mirror dialog box with the Tools ➪ Mirror menu command. 3. In the Mirror dialog box, select X as the Mirror Axis and Instance as the Clone Selection. Change the Offset value until the cloned leg is in position, which should be at around –2.55. NOTE The mirror axis depends on the viewport, so make sure that the Left viewport is selected. Any changes made to the dialog box are immediately shown in the viewports. 4. Click OK to close the dialog box. NOTE By making the clone selection an instance, you can ensure that any future modifications to the right half of the figure are automatically applied to the left half. Figure 8.6 shows the resulting robot — which won’t be falling over now. 226 13_381304-ch08.qxp 7/7/08 3:02 PM Page 227 Cloning Objects and Creating Object Arrays FIGURE 8.6 A perfectly symmetrical robot, compliments of the Mirror tool Cloning over Time Another useful way to create multiple copies of an object is to have an object be created based on its position during a specific frame of an animation. This cloning at specific times is accomplished with the Snapshot feature. Using the Snapshot command The Snapshot command creates static copies, instances, references, or even meshes of a selected object as it moves along an animation path. For example, you could create a series of footprints by animating a set of footprints moving across the screen from frame 1 to frame 100, and then choose Tools ➪ Snapshot and enter the number of steps to appear over this range of frames in the Snapshot dialog box. The designated number of steps is created at regular intervals for the animation range. Be aware that the Snapshot command works only with objects that have an animation path defined. You can open the Snapshot dialog box by choosing Tools ➪ Snapshot or by clicking the Snapshot button (under the Array flyout on the Extras toolbar). Snapshot is the second button in the flyout. In the Snapshot dialog box, shown in Figure 8.7, you can choose to produce a single clone or a range of clones over a given number of frames. Selecting Single creates a single clone at the current frame. 227 8 13_381304-ch08.qxp Part II 7/7/08 3:02 PM Page 228 Working with Objects When you enter the number of Copies in the Snapshot dialog box, a copy is placed at both the beginning and end of the specified range, so if your animation path is a closed path, two objects are stacked on top of each other. For example, if you have a square animation path and you want to place a copy at each corner, you need to enter a value of 5. NOTE FIGURE 8.7 The Snapshot dialog box lets you clone a Copy, Instance, Reference, or Mesh. TIP The Snapshot tool can also be used with particle systems. Tutorial: Creating a path through a maze The Snapshot tool can be used to create objects as a model is moved along an animated path. In this example, you create a series of footsteps through a maze. To create a set of footprints through a maze with the Snapshot tool, follow these steps: 1. Open the Path through a maze.max file from the Chap 08 directory on the DVD. This file includes a set of animated footprints that travel to the exit of a maze. 2. Select both footprint objects at the entrance to the maze. 3. Choose the Tools ➪ Snapshot menu to open the Snapshot dialog box. Select the Range option, set the number of Copies to 20, and select the Instance option. Then click OK. Figure 8.8 shows the path of footsteps leading the way through the maze, which are easier to follow than breadcrumbs. 228