Part 1: Creating the Casing Curves

In this section, you will use Keypoint curves to create the outline of the MP3 player casing.

You will choose millimeters as the units for measurement and building, and use X, Y, Z coordinates to accurately position the curves.

To save time, you will build only one quarter of the geometry, and use symmetry to create the full model.

The dimensions of the casing are shown below:

Creating a New File

For this tutorial, you will create a file and work from the dimensioned drawing to create your model.

Watch Part 1 of the tutorial.

Choose File > New to open the File Browser.
If you already have a file open, you will be asked if it is OK to delete the current file.

Answer Yes.

An empty file is created.

Setting Up Modeling Units

When you are using dimensions to specify a model in Alias, you first need to select which units to use.

All the commonly used units are available:

For this tutorial, you will be working in millimeters, so first you will ensure that the modelling units are set to mm.

Choose Preferences > Construction Options . In the Units section, open Linear and check that the Main Units are set to mm. Close the window.

To help you visualize the scale of the new model, you will change the grid spacing.
Choose Construction > Grid Preset and double-click the icon to open the option window.
Set the Grid Spacing to 10.0 mm in the Preset Grid Options window.
Click Go to change the grid.
Maximize the Top window.
Zoom into approximately 10 grid squares vertically; this will give you a good view for the size of the MP3 player.

Creating the Casing Curves

First, you will create the side and top curves of the MP3 player casing.

Choose Curves > Keypoint Curve Toolbox, then Keypoint Curve Tools > Lines > Line and use the (Windows) or (Mac) key to the start of the line to the origin.
Grid Snap the end of the line to the grid point 4 grid squares up to create a vertical line 40 mm long.
With the curve still selected, choose Transform > Move and type in -25,0,0 at the prompt window to move the curve 25 mm to the left in the x-direction.

TipIf the last coordinate numbers are zero, then you can omit them. For example, 25,0,0 can be entered as 25 only. However, a coordinate of 0,0,25 needs to be entered in full.

Next, you will create the arc for the top of the MP3 player.

The arc will define one half of the design, which will later be mirrored. It is therefore important that the arc is tangent to the center line, so that it will create a smooth result when it is mirrored.

So first, you will create a horizontal construction line to help create a tangent arc.
Choose Curves > Keypoint Curve Toolbox, then Keypoint Curve Tools > Lines > Line and use the (Windows) or (Mac) key to to the grid point at 0,40,0.
Using the , click to the right of the grid to create a horizontal line.

NoteThe length of the line isn't important; it just needs to be snapped to the center grid line, and be horizontal.

Now you will create the arc at the top of the MP3 player.
Choose Curves > Keypoint Curve Toolbox, then Keypoint Curve Tools > Arcs > Arc Tangent to Curve .
You are prompted to
```
Select the curve at location to make arc tangent to. 
```
Click the horizontal line and, without releasing the mouse button, drag the start point to the left end of the line, where it meets the grid.

NoteThe arc start point automatically snaps to the line, so you don't need to use the curve snap ( and (Windows) or and (Mac)).
You are prompted to
```
Enter end point of tangent arc.
```
Type -30,38,0 to position the end point.

TipThe coordinate given for the end point gives you an arc similar to the design shown at the start of this tutorial.

TipIf you want to modify the arc, and design your own shape, choose Curves > Keypoint Curve Toolbox, then Keypoint Curve Tools > Drag Keypoints and click and drag the end of the arc until you achieve the desired curve. The curve remains tangent to the center line.
You no longer need the horizontal line, so choose Pick > Object to select it, and press the key to delete it.

Now you will use the Curve Fillet tool to create a smooth corner.
Choose Curve Edit > Create > Fillet Curves .
You are prompted to choose a curve.
Pick the vertical line.
Then you are prompted to choose a second curve.
Pick the arc.
When prompted to adjust the fillet radius, type in a value of 7.5.
Click Accept to create the fillet curve.

TipGuidelines may be created when you use keypoint curves. They appear as dotted lines which highlight when the cursor is near. They can be useful when laying out a design, but you don’t need them for this tutorial.

To delete the guidelines, choose Delete > Delete Guidelines from the menu.