Opening the tutorial file (optional)

If you successfully completed Part 2, proceed to the next step: An overview of lights used in Alias below.

If you were not successful in part 2, open the file called Render_Basics_part3.wire, located in the wire directory of the CourseWare project. This file contains the completed model from Part 2.

Watch Part 3 of the tutorial.

An overview of lights used in Alias

Lights illuminate objects. If your scene contains no lights, it will render entirely black.

There are different types of lights you can use:

• Ambient Light
• Directional Light
• Spotlight
• Point Light
• Linear Light
• Area Light
• Volume Light

For most of your scenes, you will use one Ambient light and either a Directional light or Spotlight for the main lighting effects. Additional lights may be used occasionally, to create special lighting effects or to fill in dark areas.

Default Lights

When you choose WindowDisplay > Hardware Shade , a set of default lights are automatically created to light your scene.

The default lights are one Ambient and one Directional light.

Lights in the Multi-lister

When you create lights, they are listed in the Multi-lister.

If you double-click a light icon in the Multi-lister, you open the Light editor. This is where you can set and edit the light parameters such as Intensity and Color.

Lights in the Modeling Windows

Lights are also shown in the modeling windows. This allows them to be positioned and rotated, so that lighting and shadows can be accurately controlled.

The lights are shown as green symbols (yellow when selected), a different one for each type of light.

The light symbols can be toggled on and off using the Show panel on each window pane.

Shadows

The shadows a light casts can be used to help compose the scene.

In hardware shade, a virtual Ground plane can be enabled, which allows shadows to be cast. You can choose to cast these shadows from one of your lights, or from some preset lighting options.

In Software rendering (Render > Render ), shadows will be accurately calculated as the light falls on the geometry. So, for example, you will need to create a floor surface for shadows to be cast onto a floor.

Lighting your Scene

Now, you will apply these concepts to the lighting in your scene.

The initial Hardware Shade settings use a preset lighting option, which only gives you limited control over lighting in the scene.

Instead, you will use the default lights listed in the Multi-lister to light the scene. This will give you complete freedom to adjust the lights and shadows.

First, you will modify the Hardware Shade options to display the effects of the default lights in the scene.

1. Choose WindowDisplay > Hardware Shade ❒ to open the option window.

   In the Light source option of the Settings, choose ALL LIGHTS.

   

   The lighting on your model changes, showing the effect of the Default lights in the Multi-lister.

   In Enable Environment Effects, turn on Ground Plane.

   Click Shade on.

   

Shadows on a Ground Plane

Next, you will display the shadows cast by the lights, so you can design the lighting for your scene.

First, you will enable the ‘virtual ground plane’ in the Environment shader. This is an invisible floor plane that catches the shadows, but does not appear rendered in the scene.

1. Double-click the Environment shader to open its option window.

   

2. Click the Hardware tab at the top of the option window.
3. Open the Ground Plane section.

   

4. Check the Shadows box (if unchecked), and set Shadow Position to USER DEFINED.
5. Set Shadow Blur and Shadow Transparency until you get an acceptable shadow in the shaded view.

   

6. Close the Environment window.
   NoteIf the shadow disappears after setting Shadow Position to USER DEFINED, open the Light editor for each of your lights, and set Ground Plane Shadows to ON. See Lights in the Multi-lister.

Changing the Light Direction

Now, you will rotate the Directional light to modify the shadow direction.

1. Choose Layouts > All Windows > All Windows or F9 to show all four windows.

   

   In the Top window, the two lights are shown, but are partly hidden by the model.

2. In the SHOW button in the Top window, choose Model to remove the wireframe view. This makes it easier to see the lights in the scene.

   

   The two default lights are shown as green symbols.

3. Choose Pick > Object and select the Directional Light.

   

   TipYou can Transform > Scale the light symbol to make it easier to see. This will not change the lighting effects.
4. Choose Transform > Rotate and use the to rotate the light in the z-axis.

   

   Observe the effect on the shadow in the perspective view, and position the shadow so that it falls to the right side of the bottles. This shadow position helps to emphasize the design of the finger grip.

   

   TipIt is often easier to view and manipulate the lights in the 2D windows than in the Perspective window.

Creating a New Light

Now that you have changed the light to create an interesting shadow, the lighting on the bottles has changed.

You will now create another light to fill in the dark areas.

1. Choose Render > Create Lights > Directional .
2. You are prompted to place the light in the scene. In the Top view, click near the origin to place the light.
   NoteThe location of a directional light does not affect the lighting in the scene, only the rotation of the light makes a difference.

   

3. With the light still selected, choose Transform > Rotate and click and drag the to rotate the light in the y-axis.

   

4. Observe the direction of the light in all the windows, and continue to rotate it in any of the three axes, until it is illuminating the dim areas of the bottles.

   

   

The bottles may be over-lit, as the new light has an Intensity of 1. Now, you will modify the second light using the Multi-lister.

1. Choose Render > Multi-lister > Lights.

   

   The new light is shown in the Multi-lister.

2. Double-click the new light icon to open the option window.

   Open the Common Parameters section, and reduce the intensity to around 0.5.

   

3. Check the shaded view and adjust the light intensity further, if necessary.

   

Save your work

1. Save your work in the wire directory of the Lessons project.
2. Name your file myRender_Basics3.wire.