To create a normal map you need two files, the source and the target. The source model is generally a higher resolution and more detailed version of the target model. The target has the geometry you actually want for your scene.

To open the high resolution model

1. Select File > Open Scene.
2. Navigate to GettingStarted/UVMapping and select Toad_hi_res.mb.
3. Click Open.

   A high resolution polygonal toad model appears in the scene.

   

4. Tumble the view around the toad model.

   Maya may respond slowly because the mesh is highly detailed. You can see exactly how detailed it is by turning on the Poly Count display.

To turn on the Poly Count display

1. Select Display > Heads Up Display > Poly Count.

Statistics about the scene appear in the top left corner of the main viewport. This model consists of over a hundred thousand faces just for the head and upper torso. Loading such a high resolution model into the scene is impractical for performance purposes.

Now compare the high resolution mesh with the low resolution alternative.

To import the low resolution model

1. Select File > Import.
2. Navigate to GettingStarted/UVMapping and select Toad_lo_res.mb.
3. Click Open.

   A low resolution polygon model loads on top of the high resolution toad model.

4. Select the high resolution model and hide it by pressing + H.

The low resolution model is much more manageable in size with just over 1500 faces. However, while it maintains the basic shape of the high resolution toad, it lacks much of the detail.