Focus the cursor on the model view and using your keypad with the Num Lock off you can,

Centralise the model  - Pg Up or Pg Dn keys

To configure, right click on the view and select preferences.

Under Navigation select Cad-like and Travel speed Slowest to begin.

Enjoy !

More detailed information below.

Navigating in Cortona

Moving through a 3D Space is similar to moving a camera. Think of a video camera that captures images in the real world and converts them into electronic signals for viewing on a screen; it has a position and orientation, and these are independent attributes. Use the camera controls on the vertical toolbar to move the camera through the 3D Space. This concept assumes that there is a real person viewing and interacting with the VRML world. The VRML author may place any number of viewpoints (or cameras) in the world - interesting places from which the user might wish to view the world. Only one viewpoint may be active at a time. This section describes the mechanisms that Cortona provides for Navigating in a three-dimensional space.

Using Viewpoints

A viewpoint describes a position and orientation for viewing the scene. The VRML author will probably want to guide the user to the best vantage points for viewing it. Not all worlds contain viewpoints, but when they do, you can use them.

To activate a viewpoint:

·          Click the VIEW in the horizontal toolbar or choose viewpoints from the pop-up menu, and then select a viewpoint from the list of the predefined viewpoints.

• Click the arrow buttons to move to the next or previous viewpoint.

Note:
If there are no predefined viewpoints in a world, the Empty message appears.

Moving around: Walk, Fly, and Study

There are three main navigation modes that Cortona offers: WALK, FLY, and STUDY. You can switch the navigation mode by clicking buttons on the vertical toolbar. Each navigation mode may have several options: PLAN, PAN, TURN, and ROLL. The combination of navigation mode and its option determines the possible camera motion and its orientation.

You can navigate with the mouse, the keyboard, or both mouse and keyboard. To move around a 3D world using the mouse:  

1. Choose a navigation mode.
2. Position the pointer anywhere in the 3D window and press the left mouse button.
3. Move the mouse while holding down its left button. The direction in which you drag the mouse determines the camera motion.
4. Release the left mouse button to stop moving.

Note: The distance that you drag the mouse determines the speed with which the camera moves. If you stop moving the mouse, the camera will continue moving until you release the mouse button.


  and  
Use WALK+PLAN to move in a horizontal plane.

Forward - move closer
Backward - move further
Right - turn to the right
Left - turn to the left

Note: Move the mouse forward or backward while holding down the Ctrl key to turn upward, downward.
Move the mouse left or right while holding down the Shift key to move left or right.

 and 
Use WALK+PAN to move left or right in a horizontal plane.

Right - move right
Left - move left

Note: When you move the camera right or left, the world will appear to move in the opposite direction.

 and 
Use WALK+TURN to change the angle of the camera in a world.

Forward - turn upward
Backward - turn downward
Right - turn to the right
Left - turn to the left


 and 
Use FLY+PLAN to move left or right.

Forward - move the camera forward towards its longitudinal axis
Backward - move the camera backward
Right - turn the camera to the right around its vertical axis
Left - turn the camera to the left around its vertical axis

Note: The camera's vertical axis may be inclined in a 3D Space.
Move the mouse while holding down the Ctrl key to switch FLY+TURN.
Move the mouse while holding down the Shift key to switch FLY+PAN.


 and 
Use FLY+PAN to move up, down, left, or right within a single vertical plane.

Forward - move up
Backward - move down
Right - move right
Left - move left

Note: When you move the camera, the world will appear to move in the opposite direction.

 and 
Use FLY+TURN to turn the camera.

Forward - turn the camera upward around its horizontal axis
Backward - turn the camera downward around its horizontal axis
Right - turn the camera to the right around its vertical axis
Left - turn the camera to the left around its vertical axis


 and 
Use FLY+ROLL to incline the camera.

Right - incline to the left
Left - incline to the right


 and 
Use STUDY+PLAN to examine an object from various angles.


Forward - move the camera forward
Backward - move the camera backward
Right, Left - move the camera around the point which is defined by the pointer position where you press the left mouse button. If there is no any face there, the scene coordinate origin is considered.


 and 
Use STUDY+TURN to examine an object from various angles.

Select STUDY and TURN from the vertical toolbar. Position the pointer over the object you'd like to examine. Press the left mouse button. Drag the mouse to move the camera around the point on the object where you press the button.

 and 
Use STUDY+ROLL to incline the camera around the selected point. Select STUDY and Roll from the vertical toolbar. Position the pointer over the object. Press the left mouse button. Drag the mouse to incline the camera around the point on the object where you press the button.

Right - incline to the left
Left - incline to the right



Use GOTO to move close to object in a world. Select GOTO in the toolbar and then click on an object in the world. You'll move directly to it.

Restore, Fit, and Align

Cortona provides three mechanisms that can help to re-orient a camera if you have lost your way in a world. Unlike the navigation tools, these buttons invoke predefined actions that take place as you click on them. 

 
Use RESTORE to automatically return to the loaded world's original active viewpoint.

 
Use FIT to make the scene view fully visible in the Cortona 3D window.  

 
Use ALIGN to position the camera's horizontal and longitudinal axes parallel to the scene horizontal plane.  

Using Keyboard for Navigating

You can control the camera using keyboard commands:

• Arrow Up - move closer.
• Arrow Down - move further.
• Arrow Right - turn to the right.
• Arrow Left - turn to the left.
• Arrow Up on the numeric keypad - move closer.
• Arrow Down on the numeric keypad - move further.
• Arrow Right on the numeric keypad - move to the right. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
• Arrow Left on the numeric keypad - move to the left. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
• 7 on the numeric keypad - turn to the left.
• 9 on the numeric keypad - turn to the right.
• Gray Plus - move up in the case of FLY mode.
• Gray Minus - move down in the case of FLY mode.
• 1 on the alphanumeric keyboard - incline to the left. Note: It is not accessible in WALK mode.
• 2 on the alphanumeric keyboard - incline to the right. Note: It is not accessible in WALK mode.
• 3 on the alphanumeric keyboard - turn upward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
• 4 on the alphanumeric keyboard - turn downward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.

To accelerate the camera's movement or rotation: Press Shift, Ctrl or Shift+Ctrl and one of the above keys simultaneously.  

Setting Cortona Options

To add or delete a toolbar button:

1. Position the pointer over toolbar and press the right mouse button.
2. Choose the name of the desired button from the list.

The following options are supported from the pop-up menu of 3D window:

• Viewpoints.  Activates a list of the predefined viewpoints.
• Headlight On.  Cortona automatically includes a light for the viewer in every world. The headlight always shines directly in front of the camera. You can switch the headlight on and off.
• Navigation.  You can select a navigation mode.
• Speed.  Controls the rate at which a camera moves through a world.
• Show Toolbars.  You can show or hide toolbars.
• Show Console.  Show or hide the VRML console containing errors or warnings (for VRML developers).
• Renderers.  Select a rendering mode. To draw the 3D image, Cortona provides two hardware renderers: OpenGL and DirectX. If your system has hardware acceleration for either OpenGL or Direct3D (note: you must have DirectX 5 or greater installed), choose the appropriate renderer. Using hardware renderers can introduce limitations. Select a renderer to compare the performance and visual quality of hardware versus software rendering and set your preferences accordingly.

Note: There are differences in pop-up menu of 3D window in Cortona running under Internet Explorer and Netscape Navigator.

In Internet Explorer to display the Cortona Properties dialog box, choose Preferences... from the right-button pop-up menu.

Rendering hints

• Optimize texture for speed. All textures are optimized for speed.
• Optimize texture for quality. All textures are optimized for quality. Note that if you select both Optimize texture for speed and quality, the renderer uses the available resources to optimize speed and quality simultaneously.
• Do not render textures. To turn the textures on or off.
• Wireframe View.  The object appears to be outlined with wires rather than solid.
• Anti-alias geometry edges. The technique for smoothing out jaggies in showing curves on computer monitor.
• Dither colors if needed. Controls whether Cortona dithers while rendering. Dithering improves the quality of rendering, but may lower performance.
• Automatic level of detail. Automatically reduces the number of polygons which are displayed for any object at large distances (tiny objects on computer screen) from the viewer.
• Use textures mip-mapping. When the scene contains acutely angled polygons that disappear into the distance, mixes low- and high-resolution versions of the same texture to reduce the jagged effect.
• Motion blur effect. Apply a motion blur effect. This actually makes an image seem a little blurred in motion.

Collision detection.  By default, Cortona will allow you to pass through objects in your path. To prevent from passing through objects, choose Always at the Navigation tab.
Background color.  You can change a background color of Cortona 3D window (it is not accessible in Netscape Navigator): Click the Background color box at the General tab, click the desired color from the palette, and then click OK.
VRML authors can also control a color that simulates ground and sky.

Interacting with the Scene

Some of the objects in the scene may provide special effects that allow the user to interact with the scene in different ways. As you position the pointer over the object, containing a VRML sensor, the pointer changes:

•   Touch Sensor. Detects a click or the pointer over the object. The sort of activity in the scene is decided by the VRML author.
•   Anchor. Clicking will link to the other object, VRML world or HTML document.
•   Cylinder Sensor. Transforms pointer motion into a rotation of the object around its axis.
•   Sphere Sensor. Transforms pointer motion into a rotation of the object around its two axes.
•   Plane Sensor. Transforms pointer motion into a moving of the object.
•   Drop Sensor (VRML extention). Handling a drag-and-drop operation. Retrieves an object's uniform resource locator (URL) of an object (resource) dragged to the 3D window.