Introduction

In this tutorial you will learn how to use Lattice Rig to stretch a part of a model.

Part 1: Simple stretching

Generate the lattice

1. Open showergel_shape_modify.wire. This file is located in the CourseWare directory on the Documentation CD that came with Alias.
2. Choose Object Edit > Dynamic Shape Modeling > Lattice Rig to open the Lattice Rig toolbox.
3. Select all surfaces of the shower gel tube model.
   
4. Click Accept Targets to create the lattice.
   

Use the lattice to stretch the model

1. In the Lattice Rig toolbox, click on the Toggle Lattice Engage State tool.
   

   Notice the lattice is now drawn with solid lines, and the surfaces have a yellow-green highlight.

   
2. Use the and click on the four top points of the lattice. Notice that they now have arrow manipulators attached to them.
   
3. Click, using the , and drag any one of the blue arrows and move the points upwards.
4. Release the mouse button. Notice that the shower gel bottle has stretched proportionally.

This is a simple stretch. Notice how all parts of the bottle were stretched, including the hook. In the next part, you will learn how to stretch only part of the model.

Part 2: Stretch everything except the hook of the bottle

Sometimes it is important that parts of your model are preserved when you use Lattice Rig to modify other parts of the same model. One way to accomplish this task is to include as Lattice Rig targets only those parts that should be modified. However, there are times when this isn't possible. For example, you may need to hold half of the same surface (or mesh) as you modify another half. This tutorial will show you how to modify the lattice to achieve this.

Follow the steps in Generate the lattice of Part 1 of this tutorial to load in the bottle model and to generate the initial lattice. In this part, we will modify the initial lattice to include only the part of the bottle we wish to modify, and then perform the stretch.

Modify the lattice

1. Choose Layouts > Front to switch to the side view.
2. Using the , draw a pick box around the bottom points of the lattice to select them. Notice the arrow manipulators.
3. Click and drag the blue arrows upwards using the . This moves the bottom of the lattice up. Position the bottom of the lattice just above the point where the hook meets the bottle.
   
4. Release the mouse button. Notice that the bottom of the lattice is now drawn in red. This shows that the Lattice Rig understands that part of your target surfaces are outside of the lattice. Target geometry outside of the lattice is never modified (its shape is preserved.)
   

   The parts of the lattice that intersect with target geometry are locked. When the lattice is engaged, locked points cannot be moved.

5. Engage the lattice by clicking the Toggle Lattice Engage State tool in the toolbox.
6. Using the , draw a pick box around the top points of the lattice. Notice that the bottom points are now unselected.
7. Using the blue arrow manipulators attached to the top points, pull the top of the lattice upwards. Release at the point of your choosing.
8. Notice that the part of the shower gel bottle within the lattice has stretched according to your change to the lattice, and that the hook outside the lattice retains its original shape.