Introduction

In this tutorial, you will learn how to use the Transformer Rig to change the roof of a car to give it a different centerline.

Part 1: Setting up the rig by adding targets and constraints

In this part of the tutorial, you will learn how to set up a rig to modify the roof of the car. Specifically, you will learn how to associate existing surfaces of this model as target and constraint surfaces in a rig.

1. Open tutorialCar.wire. This file is located in the CourseWare/wire directory on the Documentation CD that came with Alias.
2. You can see the whole car. All but the surfaces corresponding to the greenhouse (the roof, the A pillars and the B pillars) are in the layer named body and that layer is in Reference state. Click on the square on the right of the name of the body layer in the layer bar to make this layer invisible.
   

   We only need to work with the surfaces of the greenhouse.

3. Choose Object Edit > Dynamic Shape Modeling > Transformer Rig to open the Transformer Rig toolbox.
4. Choose Layouts > Top to open the top view at full size.
5. Use the and draw a pick-box around the middle surfaces as shown in the figure, and click Accept Targets to select the roof surfaces as target geometry in the rig.
   
6. Click the Add Constraints tool in the Transformer Rig toolbox, and select the remaining surfaces on both sides of the roof. Click Accept Constraints to add these surfaces as constraints in the rig.
   

   The word Tan means the constraints are all tangential constraints. The pale green dots that appear inside the target surfaces are part of the clamp visualization, and the color indicates that the target surfaces are free to be modified in the current rig.

   In the Transformer Rig, any existing geometry can be used as modifiers or constraints. You can also create geometry to use as modifiers or constraints. You will do so in Part 2 of this tutorial.

7. Choose Pick > Object to leave the Transformer Rig toolbox for now.
   

The target surfaces are picked, and they have history. History for Transformer Rig is created immediately after you have picked the initial set of surfaces as targets. Whenever you wish to re-enter the Transformer Rig tool to edit the rig, use Object Edit > Query Edit and click with the on any of the target surfaces.

Part 2: Create a new surface to use as the modifier

In this part of the tutorial, you will learn how to create a surface that will be used as a modifier for the rig you have created in Part 1. You will be shown how to create a modifier surface customized for the targets in the rig, and also customized for the modification in mind.

1. Choose Curve Edit > Create > Duplicate Curve. Use the and click on the dashed line in the center of the middle surface of the roof.

   You have just duplicated the centerline of the roof.

   
2. Choose Transform > Move, and using the , drag the curve down to below the A pillar, as shown in the figure. Leave the curve picked.
   
3. In the main menu, choose Edit > Duplicate > Mirror, to open the option window of the Mirror Duplicate function.
   

   Make sure XZ is set. Click Go.

   The curve is now duplicated and the new copy appears above the A and B pillars.

   
4. Use the to click on the bottom curve so that both curves are picked.
5. Choose Layers > New to create a new layer. Name the layer Curves.
6. Assign the two curves to the Curves layer.
   
7. Choose Surfaces > Skin. Click the bottom curve, then the top curve. A new surface is created.
   
8. Choose Delete > Delete Construction History. Click Yes in the dialog that warns you about deleting history on active objects.
9. Create a new layer, name it Modifiers, and assign the skin surface to it.
10. Choose Object Edit > Query Edit. Click any target surface of the greenhouse to re-enter the Transformer Rig tool.

    The green and red visual highlights reappear. This indicates that you have returned to editing the rig that you have set up in Part 1 of this tutorial.

11. Choose the Add Free Modifiers tool from the toolbox, and click on the skin surface to select it.
    

    Click Accept Modifiers to confirm.

    
12. Click Go. A popup window may appear to notify you that the Transformer Rig history has been set up. If so, click OK to continue.
13. Choose Pick > Object to leave the Transformer Rig tool.

Part 3: Change the modifier

Now that we have completed the set-up of the rig, this part of the tutorial will show you how to use regular Alias functionality to make changes to the modifier geometry. Through Transformer Rig history updates, the target geometry (the roof surfaces) will update accordingly. This shows you the power of the Transformer Rig — your update to a single simple surface will update multiple surfaces in unison.

In this case we will use the Move CVs and Hulls tool, located at the bottom of the modeling control panel. You are free to use whichever tool you are comfortable with to change the modifier surface.

1. Make the Curves layer invisible.
2. Choose Pick > Object, and use the to pick the modifier surface.
3. In the control panel, turn on the CV/Hull option under Display. Notice that the CVs for the modifier surface are now displayed.
4. Choose Pick > Nothing, followed by Pick > Point Types > CV. Switch to the Side view, and pick the two topmost CVs. This actually corresponds to two rows of CVs of the modifier surface.
5. Click the Move CVs and Hulls tool. Under mode, choose SLIDE.
   

   Orange and yellow arrows appear beside the selected CVs.

   
6. Using the , click one of the yellow arrows in the modeling window. Drag the mouse towards the left, and notice the modifier surface becoming "flatter". Continue to slide the CVs until the leftmost arrow touches the next CV to the left, as shown here:
   
7. Release the mouse button. Notice that the target surfaces change according to the change you have made to the modifier surface.
8. To quickly compare your change to the original shape of the target surfaces, use Object Edit > Query Edit to reenter the tool (see Part 2), double-click on the Transformer Rig icon in the toolbox to open the option window, and click on Show All Geometry. Optionally, turn off Draw Clamp Visualization under the Visualization section. You should then see something like this:
   

   The green surfaces are the target surfaces post-modification. The cyan line is where the modifier is. The dark gray lines are the templated version of the original target surfaces. You can see how much you've flattened the surface.