Modeling a Helicopter

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Autodesk VIZ has a powerful Shell modifier that will help you build thin- or thick-walled objects, like an airplane fuselage or an exploded view of an electric razor. This lesson will give you some experience using this useful modifier.

Exploded helicopter body

Set up for this lesson:

Before getting started with the Shell modifier, you'll work on a model of a helicopter body.

Choose File menu > Open and browse to the tutorials\new_modeling folder. Open tut_copter_body_start.max.

The scene contains a low polygon model of a helicopter.

Apply the Shell modifier:

Now that you've seen the scene, let's go ahead an apply the Shell modifier to the body of the helicopter.

Select the body of the helicopter, Copter Body01.
Right-click to open the quad menu and choose Isolate Selection.

The body of the helicopter is now the only visible object. There is a small dialog displayed that warns you that you are in Isolation Mode.
Open the Modify panel, and click the down arrow to the right of the Modifier List.
Scroll down the list and select Shell.

Notice what happens to the model when the Shell modifier is applied without changing any values. There is an inner body and an outer body, and the face normals are oriented correctly for the inner surfaces. In the previous illustration, you could see through the model.
In the Parameters rollout, change the Outer Amount value to 5. This will be the primary thickness of the fuselage.
Click the Exit Isolation Mode button in the Warning: Isolated Selection dialog in the to see all the components again.
Click the Zoom button and zoom out a little to see the whole model, if necessary.
Press the H key to open the Select Objects dialog and choose Left Door. Hold down the Ctrl key and also choose the Right Door. Click Select.
Open the Modify panel again and apply the Shell modifier to these two objects.

Since they're virtually the same object they'll use the same Shell settings.
For the doors, change the Outer Amount value to 4.25. You can either type in the new value, or drag the spinner to set the value.
Press the H key again, to reopen the Select Object dialog. Select the Front Window object, then hold down the Ctrl key and select both Left Window and Right Window01. Click Select.

Now, all three objects are selected.
Open the Modify panel again and apply the Shell modifier to the windows.

All these surfaces will also use the same Shell settings.
For all the windows, change the Inner Amount and Outer Amount values to 3.

By reducing the Inner and Outer Amount values, you'll end up with a lip around the edges. While the lip looks good, you can see at the corners that it's pinched a little. You'll fix that next.

Refine the Shell settings:

When applying the Shell modifier to objects that have multiple segments, you might encounter edges that look bulging or corners that are pinched. You can easily correct such conditions.

Select the Front Window object.
Scroll to the bottom of the Parameters rollout and turn on Straighten Corners.

The left image shows a wider edge where the front window meets the body. In the right image, the corner is shifted to straighten out the edge.

The same pinching and bulging phenomenon is occurring to the body of the helicopter.
Select the Copter Body object and turn on its Straighten Corners switch.

The top edge along the front window and over the door looks much better.
From the Files menu, choose Save As and save your scene as my_copter1.max.

Next, you'll get a feel for how materials are handled when using the Shell modifier.

Use the material overrides:

The color of the helicopter is based on the object colors used when the model was created. Next, you'll apply a material and adjust what surfaces are affected by using the overrides for the inner, outer, and edge material IDs.

Select the Copter Body object and press the M key to open the Material Editor.

The upper-left material is a Multi/Sub-object material named Helicopter, containing three sub-materials.
Click the material and drag it on to the Copter Body.

Tip: Watch for the object name tag that pops up as you drag over it. The name tag can be very useful in congested scenes.

The default material IDs place the colors all over the model. Suppose you want the entire outer body of the helicopter to be white, with a red interior and blue edges around the doors and windows.
Right-click the Copter Body and turn on Isolate Selection so you can see the inner surfaces.
In the Parameters rollout, turn on Override Outer Mat ID.

The Outer Mat ID field becomes active.
Change the Outer Mat ID value to 2.

The outer surfaces turn white.
Turn on the Override Inner Mat ID switch.

The inner surfaces change to red. You don't have to change the Inner Mat ID because the first sub-material is red.
Turn on the Override Edge Mat ID switch and set the Edge Mat ID value to 3.

The edge surfaces turn blue.
Turn off Isolation mode.
Select the Left Door and Right Door.
Click the Helicopter material and drag it to the Left Door.

The Assign Material dialog appears.
In the Assign Material dialog, make sure Assign To Selection is turned on and click OK.

This assigns the material to both doors.

The material assigned to the doors
On the Parameters rollout, first turn on the Override Inner Mat ID but leave the Inner Mat ID set to 1.
Turn on Override Outer Mat ID and set the Outer Mat ID to 2.

The outer doors turn white.
Turn on the Override Edge Mat ID switch and set the Edge Mat ID to 3.

The doors show blue edges.

The windows look pretty good with the light blue, so you can leave them alone.
Save your scene as my_copter2.max.

Refine the model with MeshSmooth:

Modifiers that you add after applying a Shell modifier do not adversely affect any of the settings you've made for the shell. To further refine the model, you're going to apply a MeshSmooth modifier.

Select the entire model.
On the Modify panel, open the Modifier List and choose MeshSmooth.

MeshSmooth is applied to the model.
In the Subdivision Method rollout, choose Classic.

This results in closing the gap between the window in the door and the frame of the helicopter.
In the Subdivision Amount rollout, set the Iterations to 2.

This smooths the body of the helicopter.

The next procedure gives you a better view of all the components affected by the Shell.

Explode the components:

In these steps, you'll create an exploded view of all the parts of the helicopter.

Activate on the Select And Move tool and select the Front Window.
In the Left viewport, move the Front Window to the right, away from the body.
Right-click in the Perspective viewport and select the Left Door and Left Window.
Move the Left Door and Left Window along the X-axis away from the body.
Save the scene as my_copter3.max.

If you'd like, you can compare your model to our final version, tut_copter_body_final.max, found in the tutorials\new_modeling folder.

Summary

You have now experienced how the Shell modifier gives you the ability to create thin- and thick-walled structures. You also found that you can control material placement by adjusting the material IDs of the inner, outer, and edge surfaces of the model.