Rewind the scene to the beginning. All the joints are in the same position they were in when the tentacle geometry was skinned to the joints.

In the Outliner, select the tentacle and switch to the Animation menu set. Choose Skin >Detach Skin.

If you play the animation, you'll see that the joints still move around but the tentacle lies limp on the ground.

Create a locator and name it "shaker1."

Open the Hypershade and create a Fractal Noise 2D texture.

Open the Attribute Editor for the Fractal texture. Under Fractal Attributes, click the Animated check box. A number of additional attributes will become available.

Rewind the animation to the beginning. In the Attribute Editor for the Fractal texture, right-click over the numeric field for Time and choose Set Key (Figure 3.2).

Figure 3.2. Set keyframes on the Time Slider to animate the Fractal texture.

Move the playhead for the animation to frame 50 or so, move the slider next to the Time attribute in the Fractal texture's Attribute Editor to about 100 or so, and set another key.

Click the arrow box to the right of the Time Slider attribute and in the fractal1_time attributes, set the Post Infinity menu to Cycle.

In the Outliner, select the shaker1 locator and MMB drag it to the work area in the Hypershade. Make sure that the new fractal1 texture is there as well.

Select the fractal1 texture and MMB drag it on top of the shaker1 locator in the Hypershade. From the pop-up menu, choose Translate (Figure 3.3).

Figure 3.3. The fractal1 texture is connected to the shaker1 locator's translate attribute.

Rewind the animation. In the perspective view, zoom in on the shaker1 locator and play the animation. Wow! That thing is bugging out!

From the Animation menu set, choose the Joint tool. Click once in the perspective view to create a single joint. Rename it "shakyJoint1."

Parent shakyJoint1 to the shaker1 locator. Set the joint's Translate values to 0 in the Channel Box so the joint snaps to the same position as the locator (Figure 3.4).

Figure 3.4. The single joint parented to the shaker1 locator

Select the shaker1 locator and use Maya 8's new duplicate special options by choosing Edit > Duplicate Special > Options. In the options, set Group Under to World and Number Of Copies to 17 and click on Duplicate Input Graph and Assign Unique Names To Child Nodes (as in Figure 3.5). Click Apply.

Our next task involves parenting each shaker joint to its respective tentacle joint (Figure 3.6). To do this we will use a little bit of MEL just to save ourselves some time and trouble. Type the following code into the Script Editor and press the Enter key on the numeric keypad to have it execute:

for ($i=l; $i<=18; $i++) {
parent ("shaker" + $i) ("tentacle_joint" + $i);
}

This bit of MEL is a simple loop that parents each of the respective shakyJoints to its respective tentaclejoint. The loop first initializes the variable $i by setting it to 1. The $i++ increments $i by 1 each time it runs, as long as $i is less than or equal to 18. In the body of the loop we append $i to the name of the parent joints and the tentaclejoints so Maya knows which objects to parent to which. It's three lines of code that saves us a whole lot of clicking.

Figure 3.6. The locators are parented to the joints in the original chain.

Play the animation. The shaking locators now follow the animation of their parent joints. All of them shake exactly the same way though, which is not what we want.

The easiest way to mix up the vibration of the joints is to rotate the place2D texture node attached to each Fractal texture. We could open the attribute for each node and randomly move the slider, or we could put MEL to work for us again and take away some of the tedium. Type the following code into the Script Editor and press the Enter key on the numeric keypad to have it execute:

for ($i=l; $i<=18; $i++){
 setAttr ("place2dTexture" + $i + ".rotateUV") (rand(360));
}

We will be skinning the tentacle to the new shaky joints, but before we do this, we have to get them as close as possible to the starting position of the tentaclejoints. If you rewind the animation, you'll notice that they are slightly offset from the position of each tentacle joint. This is because the animated fractal is now feeding the translate values for each shaky locator a random value from 0 to 1.

Open the Hypershade and switch to the Texture tab. Shift+select all the textures. In the Channel Box, find the Color Gain R, G, and B values. Set them all to 0. The shake locators should pop to the position of the tentacle joints. The fractal textures will turn black when you do this (Figure 3.7).

Figure 3.7. Setting the color gain to 0 for the Fractal textures causes the shaky joints to assume the same position as the joints in the original chain.

In the Outliner, Ctrl+select each shaky joint. Then Ctrl+select the tentacle. Alternatively, you can save some time by using the MEL select command. Type this into the command line:

select -r "shakyJoint*";

The r flag stands for replace, as in "replace the current section." The asterisk after shakeyjoint is a wildcard that tells Maya to select all the objects whose names start with "shakyJoint." Since our shaky joints are numbered 1 through 18, Maya knows to select all of them. Once they're selected, Ctrl+select the tentacle.

From the Animation menu set, choose Skin > Bind > Skin > Smooth Bind > Options. In the options, set Bind To to Selected Joints, Bind Method to Closest Distance, Max Influences to 3, and Dropoff Rate to 4.

Create a new locator and name it "shakeControl."

Open the Attribute Editor for shakeControl and choose Attributes > Add Attribute.

Name the attribute "shakeDimmer." Set Data Type to Float, and enter 0 for Minimum, 2 for Maximum, and 0 for Default (Figure 3.8).

Figure 3.8. The settings for the custom shake dimmer control

Open the Connection Editor and load the shakeControl locator on the left side.

Open the Hypershade and select fractal3 (we'll leave fractal1 and fractal2 alone for now).

In the Connection Editor, connect the Shake Dimmer attribute on the left side to the Color Gain R, G, and B values on the right. Do this for fractal3 through fractal18 (Figure 3.9).

Figure 3.9. The shakeDimmer attribute is connected to the Fractal texture's Color Gain R,G,and B.

Since fractal1 and fractal2 control the shakers nearest the thick end of the tentacle where the generator model is hooked up, we can leave their Color Gain values at 0 or near 0 just so the shaking doesn't get out of hand.

Set the Shake Dimmer attribute to 0.5 and play the animation. If all goes as planned, you should see the original animation with a bit of quaking added to the movement of the tentacle (Figure 3.10). You can keyframe the Shake Dimmer attribute so that the shaking gets worse over time. Setting it at a value between 1 and 2 will create some really crazy shakes.

Figure 3.10. The shaking joints add a dramatic deformation to our severed tentacle animation.

We have a simple pipe model and the slimy tentacle. A camera has been set up for the shot. For now, hide the tentacle.

First we'll be creating a curve that wraps around the pipe. Later on we will slide the tentacle along this curve using the IK Spline tool. However, if we draw the curve directly on the pipe, we will encounter a problem when the tentacle slides along it; namely, the thickness of the tentacle will cause it to penetrate the geometry of the pipe. To work around this, we'll create an invisible cylinder for our curve that is slightly thicker than the pipe.

Create a NURBS cylinder that fits around the pipe up to the bulge at the top of the pipe. Name the cylinder "dummy" and give it 10 spans (Figure 3.11).

Figure 3.11. A NURBS cylinder with 10 spans has been placed around the pipe.

Select the dummy surface and choose Modify > Make Live. Now we can draw a curve on the surface.

Choose Create > CV Curve Tool. In the options, make sure that Curve Degrees is set to Cubic.

Turn grid snapping on. Starting from the top of the cylinder, click on the livedummy surface to draw a curve that wraps around the cylinder. With grid snapping on, each time you click on the surface, the new CV should snap to theisoparms of the live surface. Try to draw the curve so that each CV is one spandown and two over (see Figure 3.12).

Figure 3.12. With the dummy surface live and grid snapping on, we can draw a curve that spirals around the pipe.

When you've reached the bottom, hit Enter to complete the curve.

We need to duplicate the curve drawn on the surface. Select Surface Curve and (from the Surfaces menu set) choose Edit Curves > Duplicate Surface Curves.

Rename the duplicated curve "tentacleCurve."

In the Outliner, select the dummy surface and hit the down arrow key to make it "unlive." Hide the dummy surface so you don't confuse the tentacle curve with the surface curve. We want to keep the dummy around so we can preserve the history connection between it and the tentacleCurve.

Select the tentacleCurve and choose Edit Curves > Rebuild Curves > Options. In the options, set Rebuild Type to Uniform and Parameter Range to "0 to 1", keep the ends, and set Number Of Spans to 12. Make sure it's a cubic curve and don't keep the original.

Turn on curve snapping, and from the bottom of the curve, start adding joints that follow along to the top. Make a chain of about 18 joints or so. When you've finished making the joints, you should rename them. Select the root joint in the Outliner. Choose Modify > Prefix Hierarchy Names. In the pop-up window, type curve_ and hit Enter. The joints will be renamed "curvejoint1," "curve_joint2," "curve_joint3," and so on.

Select curvejoint1 and (from the Animation menu set) choose Skeleton > Orient Joints > Options. In the options, choose Edit > Reset to switch to the default settings; these should work fine (Figure 3.13).

Figure 3.13. The curve joints are drawn on the curve that wraps around the pipe.

Select curve joint1 and the tentacleCurve and choose Skin > Bind Skin > Smooth Bind > Options. In the options, make sure that Bind To is set to Joint Hierarchy, Bind Method is set to Closest In Hierarchy, and Max Influences is set to 3. Go ahead and hit Apply to bind the curve to the curvejoints.

Set the range of the animation to 60 frames. Set the playhead to frame 60.

In the Outliner, Shift+select all of the curvejoints and set a keyframe on their X, Y, and Z rotational values.

Move back to frame 1. Shift+select joints 2 through 17.

Choose the Rotation tool and click on the green circle to rotate the Y axis. Slowly drag to the left so that the chain of joints unwinds (Figure 3.14).

Figure 3.14. Use the rotate tool to unwind the joint chain.

Set a keyframe on the rotational values of these joints.

Play through the animation. The curvejoints should wrap around the dummy surface over the 60 frames.

In the Outliner, Shift+select joints 3 through 17.

Open the Graph Editor. Marquee drag around the keyframes at the start of the animation then switch to the Move tool. Hold the Shift key down and MMB drag the keys a few frames to the right.

Control+click joint 3 in the Outliner so that it is deselected; joints 4 through 16 should still be selected. Repeat the steps1 and 2 to move their keyframes to the right.

Repeat this process of moving keys and deselecting the parent joint one at a time until you've gone through all the joints up to 17.

Reselect all the joints and compare what you see in the Graph Editor with Figure 3.15. It doesn't have to be exactly the same, just similar.

Figure 3.15. The Graph Editor shows how the animation of each joint has been offset in time.

The animation looks a bit more natural now.

Switch to the side view.

Turn the shading display to wireframe so it's easier to see what's going on. You may want to turn the resolution of the tentacle down to rough as well (select the object and hit 1 on the keypad).

Turn grid snapping on, and starting from the top of the tentacle, add joints every two units all the way down the tentacle. Hit Enter when all of the joints have been created (Figure 3.16). Use the Prefix Hierarchy command to rename these joints "tentaclejoints."

Figure 3.16. Joints have been added going down the length of the tentacle.

Smooth bind the tentacle to the tentaclejoints using the settings from the section "Adding Joints to the Curve" earlier in this tutorial.

From the Animation menu set, choose Skeleton > IK Spline Handle Tool > Options. In the options, turn off Snap Curve To Root and Auto Create Curve (Figure 3.17).

Figure 3.17. The settings for the IK Spline Handle tool

With the tool active, in the perspective view click on the tentaclejoint at the top of the tentacle, then click on the tentaclejoint at the bottom of the tentacle, and finally, carefully click on the tentacleCurve. The tentacle and its joints should jump over to the tentacle curve.

In the Outliner, select the curvejoints and turn off their Visibility (Ctrl+h) so that things are a bit easier to see.

Move to the end of the animation and switch to shaded view.

The tentacle is still offset from the pipe. In the Outliner, select the invisible dummy surface. Scale it down in X and Z until the tentacle looks like it's wrapped around the pipe properly. The history connection between the dummy surface and the tentacleCurve allows us to do this.

Switch to the camera view. From the Outliner, select ikHandle1. In the Channel Box, find the Offset attribute. It should be at 0. Set a keyframe for this value.

Move to frame 1 and set Offset to .8. Set another keyframe.

Playing through the animation from the camera view, you can see that the tentacle now moves up the pipe as it wraps around. I think this motion could be a little more obvious.

Move to frame 40 and set Offset to 0.5. Set a keyframe here. Now it's looking creepier!

You can open the Graph Editor for ikHandle1 and refine the movement of the tentacle's creep (Figure 3.18).

Figure 3.18. The tentacle slides up the pipe as it wraps around.

Open up the file extendo-LegCar_v01.mb from the chapter3 folder on the CD.

The car is hovering above the hilly roadway; its wheels are down on the ground. This is the maximum height the car will achieve. You have been instructed to create a telescopic leg that extends from the car down to the wheels. This leg will expand and contract, keeping the car level as it drives over the hills (Figure 3.19).

Figure 3.19. The legs of the car will need to reach down to the wheels in the trough between the hills when fully extended.

There is a single piece of geometry named legSection1_1 in the car's left rear wheel well. This will become our telescopic leg.

Turn off visibility for all of the display layers except the LEG and WHEELS layers.

Switch to the side view and zoom out so you can see the wheels and the leg section.

There are about 15 units between the leg section and the wheel. The leg section is one unit tall, so we'll duplicate it 15 times using the new Duplicate Special options.

Select the legSection1_1 object and choose Edit > Duplicate Special > Options.

In the options, set Geometry Type to Copy and Group Under to World. Set Translate Y to −1 and Scale to 0.9, 1, 0.9. Set Number Of Copies to 14. Hit Apply to make the copies (Figure 3.20).

Figure 3.20. The Duplicate Special options for the leg section

Select all the leg sections and choose Modify > Freeze Transformations.

From the Animation menu set, choose Skeleton > Joint Tool > Options. In the options, turn off Scale Compensate (Figure 3.21). With Scale Compensate off, all child joints will scale to the same size as their parent joint.

Figure 3.21. The Scale Compensate option has been turned off in the Joint Tool options.

Turn on grid snapping and create a joint chain down the length of the leg. Make one joint for each leg section. Place the last joint at the bottom of the final section.

Switch to the front view. Select joint1 and move it so that the joint chain is at the center of the leg geometry (Figure 3.22).

Figure 3.22. The joint chain at the center of the leg sections

In the Outliner, select joint2 through joint16. In the Channel Box, Shift+select the Rotate X, Y, and Z attributes. Right-click and choose Lock Selected.

Select joint1 and choose Modify > Prefix Hierarchy Names. In the field, type leg-Section1_.

This next part is a bit tedious, but that comes with the territory sometimes. Select legSection1joint1 and Ctrl+select the legSection1_1 geometry. Choose Constrain > Parent > Options. In the options, make sure Maintain Offset is checked and that All is selected for both Rotate and Translate (Figure 3.23). The Weight setting should be at 1. A parent constraint constrains both the translate and the rotate values. As with a regular parent connection, you can still move the child node. For our purposes, don't move the child nodes. We're using this type of constraint to save time, so we don't need to create both a point and a rotate constraint for each object.

Figure 3.23. The options for the parent constraint

In the Outliner, go down the line and create a parent constraint so that each leg-Section is constrained to its respective legSection joint. Constrain legSection1_2to legSection1_joint2, legSection1_3 to legSection1_joint3, and so on. legSection1joint16 will not need anything constrained to it. Alternatively, you coulduse a little MEL scripting to automate this process. A simple loop like the onesused in the shaky tentacle tutorial might do the trick. Type the following into theScript Editor:

for ($i=l; $i<=16; $i++) {
  parentConstraint -mo ("legSectionl_joint" + $i) ("legSectionl_" + $i);
}

The mo flag in the parentConstraint command stands for "maintain offset." If it's not specified in the command, Maya automatically constrains all axes and gives the constraint weight of 1.

When you are done, try rotating legSection1joint1 to make sure all the geometry has been constrained to the joints. If all the leg sections rotate with the jointsproperly, good work. You may now ask yourself why we didn't just skin thegeometry to the joints. Well, I'm glad you asked.

Return legSection1joint1 to its 0, 0, 0 rotational position and try scaling down in X. You'll see all the section geometry retract just like a telescopic leg should (Figure 3.24). By using constraints instead of binding, we avoid having the geometry scale with the joint. Since we turned off Scale Compensate for the joints, all the child joints scale with the legSection1joint1 joint, which means this is the only joint we have to worry about animating.

Figure 3.24. Scaling the top joint causes the telescopic sections of the leg to retract.

Select legSection1joint1 and open its Attribute Editor.

In the Limit Information section, expand the attributes for Scale.

Click the check box next to Scale Limit X and put .01 in the Min box and 1 in the Max box (Figure 3.25).

Figure 3.25. The scale limits are set for the legSection1joint1 joint.

Switch to wireframe mode in the perspective view, and from the Animation menu set, choose Skeleton > IK Handle Tool > Options. In the options, switch Current Solver to ikSCsolver. Turn off Sticky (Figure 3.26). The SC solver is a single chain solver. Since we are not concerned about the rotation of the child joints, a single chain solver will do fine (as opposed to the RP, or rotate plane, solver, which adds twist controls to adjust the rotation of the child joints).

Figure 3.26. The settings for the IK Handle tool.

With the IK Handle tool active, click on legSection1joint1 at the top of the joint chain and then click on legSection1_joint16.

Create a locator and name it "legWheel_1."

Turn on point snapping and place the legWheel_1 locator at the same location as the newly created IK handle at the bottom of the joint chain.

With legWheel_1 selected, choose Modify > Freeze Transformations to zero out its Rotate and Translate attributes.

Select legWheel_1 and ikHandle1 in the Outliner. Choose Constrain > Point to lock the IK handle to legWheel_1. Select ikHandle1 and turn off its Visibility (Ctrl+h) so you don't accidentally select it in the future.

Switch to the side view and choose Create > Measure Tools > Distance Tool.

With point snapping on, click on the joint at the top of the chain.

Zoom in closely to the legWheel_1 locator on the bottom of the joint chain, and click on it carefully to connect the Distance tool to this locator. You should see two arrows appear between a new locator at the top of the chain and the legWheel_1 locator. The number 15 should appear between the arrows (Figure 3.27).

Figure 3.27. The Distance tool measures the distance between a locator created at the top of the joint chain and the legWheel_1 locator.

Rename Locator1 "legTop_1" and point constrain the legSection1joint1 joint to legTop_1.

Select the legSection1joint1 joint and scale it down to .01 in X so that the entire leg retracts.

Select the legWheel_1 locator and translate it in Y so that it is right at the tip of the bottom of the retracted leg (Figure 3.28).

Figure 3.28. The legWheel_1 locator has been moved to the bottom of the retracted leg.

In the Animation menu set, choose Animate > Set Driven Key > Set. The Set Driven Key window will open.

In the Outliner, set the display mode so that shape nodes are available, and then scroll down and choose the distanceDimension1's shape node. Load it as the Driver in the Set Driven Key window.

Select the legSection1joint1 joint and load it as the Driven in the Set Driven Key window.

On the right section of the top part of the Set Driven Key window, scroll down and choose the Distance attribute.

In the bottom right, choose the ScaleX attribute.

Hit the Key button (Figure 3.29).

Figure 3.29. Set Driven Key creates a relationship between the distance dimension's output and the legSection1joint1 joint.

Select the legWheel_1 locator, and in the channel box, set the TranslateX, Y, and Z values to 0.

Select the legSection1joint1 joint and set the ScaleX value to 1.

Click the Key button in the Set Driven Key window.

Select all of the leg geometry and group it. Rename the group "leg_1."

Select the leg_1 group and choose Edit > Duplicate Special > Options. Set Group Under to World and Number Of Copies to 1, and check Duplicate Input Graph and Assign Unique Name To Child Nodes.

These Duplicate Special settings will duplicate all of the geometry, the joints, the locators, and the distance dimension. including the set driven keys that automate the scaling. The only thing that will not duplicate is the ikHandle.

Hide all the leg1 objects, joints, locators, and so on.

Expand the new set of joints associated with leg 2.

At the bottom of the joint chain in the Outliner, delete the effector.

Create a new IK handle using the steps described in the section "Creating an IK Handle for the Leg Joints" earlier in this tutorial. Hide it and point constrain it to legWheel_2.

Make two more duplicate legs using this process. If the newly duplicated legs appear all blue, apply a new shader to them. Sometimes the shading does not duplicate very well. Remember to rename all the joints and geometry associated with leg 2 so that instead of legSection1 they read legSection2. You can use Search and Replace Names under the Modify menu to do this.

When you have four legs, turn the visibility for the CAR layer back on.

Place the leg top locators in each of the wheel wells of the car so that legTop_1 is in the driver side front wheel well, legTop_2 is in the driver side rear wheel well, legTop_3 is in the passenger side rear wheel well, and legTop_4 is in the passenger side front wheel well (Figure 3.30).

Figure 3.30. Each leg top locator has been positioned in the wheel wells of the car model.

Arrange the legWheel locators so that they are at the center point of the cylinder attached to the inside of each wheel (Figure 3.31).

Figure 3.31. The legWheel locators are positioned at the center of each wheel's inner hub.

When you have these arranged, select each of the legTop locators and choose Modify > Freeze Transformations to zero out their translate values. Do the same for the legWheel locators.

You may want to hide the distance dimension objects just to make the scene a bit clearer.

Select legWheel_1 and then Shift+select the L_front_tire object.

Create a parent constraint between the two objects.

Do the same for the other three wheels, parent constraining the wheels to the legWheel locators.

Switch to the top view and turn on grid snapping.

Choose Create > CV Curve Tool > Options. Set Curve Tool Degree to Linear.

In the top view window, draw a triangle on the grid using four points.

Choose Modify > Center Pivot to set the pivot at the center of the triangle.

Rename the triangle frontSuspension.

Duplicate the triangle and name the duplicate rearSuspension.

Scale the triangles down a little bit and move them so that the frontSuspension object is in between the front wheels and the rearSuspension object is in between the rear wheels (Figure 3.32).

Figure 3.32. Two NURBS curves shaped as triangles are placed between the wheels. These will become controls for the front and rear sets of wheels.

Freeze their transformations once you are happy with their placement.

Parent legWheel1 and legWheel4 under the frontSuspension triangle.

Parent legWheel2 and legWheel3 under the rearSuspension triangle.

Move the front suspension object around, rotating it on its Y axis. You now have a nice control for the car's steering, yet the wheels can also move independently since they are parented under the front suspension control. To return them to their original positions, you can just zero out their transforms.

Select all the leg controls in the Outliner and add them to the LEGS display layer by right-clicking over the LEGS layer in the Layer Editor and choosing Add Selected Objects.

Turn off the visibility for the CAR, LEGS, and WHEELS layers. Turn on the visibility for the GROUND layer.

Select the road object in the perspective view, right-click, and choose Isoparms.

Select the isoparm at the center of the road. Switch to the Surfaces menu set and choose Edit Curves > Duplicate Surface Curves. Rename the new curve "carPath."

Create a locator and name it "wheelFollow."

Switch to the Animation menu set and choose Animate > Motion Paths > Attach To Motion Path > Options.

In the options, choose Edit > Reset Options. These should work just fine. We want Follow on so the locator rotates to follow the contour of the motion path.

Turn the visibility of the other layers back on, and move the playhead so that the wheel follow locator is below the car—around frame 88 or 89.

Parent the frontSuspension and rearSuspension objects to the wheelFollow locator.

Scrub back and forth on the Time Slider. You should see the wheels climb up and down the hilly road. The legs should point toward the wheels (Figure 3.33).

Figure 3.33. The wheels now follow the contour of the road since the suspension objects have been parented to the wheelFollow locator.

Set the playhead back to frame 88. Create a new locator and name it "chassis-Control."

Place the chassis control at the center of the chassis object. The easiest way to do this is to point constrain the locator to the chassis object (make sure Maintain Offset is Off in the Point Constraint options). The locator should snap to the center of the chassis. Then, in the Outliner, delete the point constraint from under the chassisControl object. Freeze transforms on the chassisControl.

Parent each of the legTop locators to the chassis control locator.

Almost there! Create yet another locator and name it "carFollow." Place it at the same location as the chassis control locator.

Point constrain carFollow to the wheelFollow object. In the options for the point constraint, turn Maintain Offset on and set Constraint Axes to Z Only.

As you scrub back and forth in the Timeline, the carFollow locator should move with the wheelFollow but maintain a level height (Figure 3.34).

Figure 3.34. The carFollow locator follows the Z position of the wheelFollow locator.

Move the Time Slider back to frame 88 and parent chassisControl to the carFollow locator.

Parent constrain the Chassis object to the chassisControl locator.

As you move back and forth on the Time Slider, the car should remain level while the telescoping suspension legs follow the road. That's one smooth ride!

If the car is moving backwards, you can select the wheelFollow locator, open its Graph Editor for the motion path node, and reverse the keyframes so that it's moving in the correct direction.

The animator has the advantage of an automated system to control the extension of the legs, but he can also independently keyframe the front and rear suspension and each of the wheels as well as the chassis. This way he can make the legs a little more wobbly as well as move the chassis around as if it's having a hard time balancing on top of the wobbly legs. Hey, this is a prototype car; it's bound to have a few kinks in it. He will certainly have to make adjustments as the car reaches the crest of each hill. A few keyframes on the chassisControl object should fix these problems.

The machine has been built as a single polygon object. The modeler has also provided a curve for the machine to follow as it makes its way through the hole (Figure 3.36).

Figure 3.36. The soda machine sits next to a black hole.

If you play the animation, you'll see a little hole open up when the curve meets the floor at about frame 20. This hole was created by projecting a circle on the floor, trimming the surface, and then setting keyframes on the scale of the projecting curve.

First let's create a lattice around the machine. Switch to the Animation menu set and choose Deform > Create Lattice.

In the Channel Box for the lattice shape, set the S, T, and U Divisions to 12.

In the Attribute Editor for the ffd1 node, uncheck the Local box. This makes the deformation smoother but a little less accurate.

Switch to the front view and turn on wireframe shading.

Zoom into the soda machine and turn on grid snapping.

Select the Joint tool and reset the settings in the Tools option window. Starting at the bottom of the soda machine, create a joint chain going straight up the center. Make each joint one unit tall so that the resulting chain is 14 joints long.

Because of the positioning of the models, the joint chain will be at the same position as the curve (Figure 3.37). Isn't that handy?

Figure 3.37. The joint chain goes up the center of the machine.

Select the joint chain and the ffd1Lattice object in the Outliner (don't select the ffdbase). Choose Skin > Smooth Bind to bind the lattice to the joints. In the options, you can use the Edit menu to reset the options to the default settings, which should work fine.

Choose Skeleton > IK Spline Handle Tool > Options. In the options, click Root On Curve and Auto Parent Curve. Turn off Snap Curve To Root and Auto Create Curve.

With the IK Spline Handle tool active, move to the perspective window and click on the joint at the bottom of the machine, then the joint at the top, and then the path curve.

Open the Channel Box for the ikHandle1 tool and find the Offset attribute toward the bottom of the Channel Box. Leave the value at 0 and set a keyframe at frame 1.

Move the playhead to frame 30 and set the offset to 1. Set another keyframe.

In the Outliner, select the ffd1Lattice object.

Choose Deform > Create Lattice to make a new lattice.

In the Channel Box for the new lattice, set the S, T, and U Divisions to 6.

In the Outliner, select both the ffd2Lattice object and the ffd2Base object. Move them over to the left so that they are over the hole in the floor. The machine should not deform when you do this. If it does, make sure you have both the lattice and the base selected. Rotate the second lattice and its base object 180 degrees in Z (Figure 3.39).

Figure 3.39. The second lattice and its base are moved over the hole, and both are rotated 180 degrees in Z.

Move the playhead to frame 19.

Adjust the second lattice and base so that they are at the same position as the machine. Move them down a little so that they're halfway through the floor.

You may want to hide the first lattice and base just so you don't get confused about what you're looking at.

Select the second lattice and scale it down in X and Z. Scale the lattice base up a little so that the machine looks like it does in Figure 3.40.

Figure 3.40. The second lattice has been scaled down in X and Z, and its base has been scaled up.

Have some fun creating a nice squash effect by adjusting the scale on the second lattice and the size of its base. Right-click over the lattice and choose Lattice Points. Select the lattice points and scale them down. It will take some tweaking to get just what you want. Move the animation back and forth and continue to fool around until it looks good.

Move to the start of the animation. If you notice that the machine is deformed in a weird way (as in Figure 3.41), it may be that the base for lattice2 has been scaled up too high. Scale it down again until this goes away.

Figure 3.41. If the soda machine is deformed in a weird way at the start of your animation, the base shape for the second lattice may be scaled too high.

Right-click over the second lattice and choose to select the lattice points.

Select the lower rows of lattice points and use the Rotate tool to rotate them in Y about 45 degrees. This should create a nice twisting effect as the machine gets sucked into the hole.

You can also set keyframes on the ikHandle's Twist and Roll attributes to enhance this twisting effect. This may require further tweaking of the lattice to work correctly. The twist control is a lot of fun to play with; experiment with it to get some interesting effects. For this particular shot, however, rotating the lattice points on the second lattice may work better (Figure 3.42).

Figure 3.42. Rotating the points of the lattice and adjusting the twist on the IK Spline Handle can create some interesting twisting effects as the machine gets sucked into the black hole.