Cortona User's Guide

The following sections contain the description of the Cortona main controls:

The Cortona Window
Navigating in Cortona
Setting Cortona Options
Interacting with the Scene
Using Cortona in HTML Documents
3D Scene Stereo Viewing

The Cortona Window

With Cortona you can see and explore 3D worlds. Cortona will start automatically when you open a file containing VRML world. There are two parts of the Cortona window:

Toolbars:
- The vertical toolbar, which contains buttons used to specify navigation type in a world.
- The horizontal toolbar, which contains buttons with predefined actions to change your position in a world.
The 3D window, which shows VRML world.

There is also pop-up menu, which you access by pressing the right mouse button while the pointer is over toolbars or 3D window.

Some worlds do not allow you navigating in a world, so toolbars may be invisible.

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.Your movements in the world continually position and orient that camera. 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. Nevertheles, 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. You can also press Page Down or Page Down keyboard button.

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. Please note that the VRML author has an opportunity to specify which navigation paradigm should be used in the scene by default. Some worlds don't allow the user to use navigation controls, but they may provide on-screen cues to navigation.

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

Choose a navigation mode.
Position the pointer anywhere in the 3D window and press the left mouse button.
Move the mouse while holding down its left button. The direction in which you drag the mouse determines the camera motion.
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. To accelerate the camera's movement or rotation, press SHIFT, CTRL or SHIFT+CTRL.

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 Space key to turn upward, downward.
Move the mouse left or right while holding down the ALT key to move left or right.

and

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

Forward - move closer
Backward - move further
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 ALT key to switch FLY+PAN.
Move the mouse while holding down the Space key to switch FLY+TURN.
Move the mouse while holding down the ALT+Space keys to switch FLY+ROLL.

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.
Note: Move the mouse while holding down the ALT key to switch STUDY+ROLL.
Move the mouse while holding down the Space key to switch STUDY+PLAN.
Move the mouse while holding down the ALT+Space keys to switch STUDY+PAN.

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. The functionality for arrow buttons corresponds to the movement of your mouse and depends on the navigation type and its option. Please note that the following description of keyboard commands is presented for the FLY+PLAN navigation.

Arrow Up - move closer.
Arrow Down - move further away.
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 the camera downward around its horizontal axis.
9 on the numeric keypad - turn the camera upward around its horizontal axis.
1 on the numeric keypad - incline to the right. Note: It is not available in WALK mode.
3 on the numeric keypad - incline to the left. Note: It is not available in WALK mode.
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 right. Note: It is not available in WALK mode.
2 on the alphanumeric keyboard - incline to the left. Note: It is not available in WALK mode.
3 on the alphanumeric keyboard - turn downward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
4 on the alphanumeric keyboard - turn upward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
Page Down - next viewpoint.
Page Up - previous viewpoint.

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

The ALT and SPACE keys allow the user to quickly change the navigation option to PAN and TURN accordingly in the FLY navigation mode (to ROLL and PLAN in the STUDY mode). The ALT and SPACE keys simultaneously pressed activate ROLL in the FLY navigation mode or PAN in STUDY.

Setting Cortona Options

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

Viewpoints. Activates a list of the predefined viewpoints.
Headlight. 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.
Full Screen. This hides most screen elements so that you can view the whole scene. To close Full Screen, press ESC or F11.
Hide/Show Toolbars. You can show or hide toolbars.
Show/Hide Console. Shows or hides the VRML console containing errors or warnings (for VRML developers).
Preferences.... Modifies settings for Cortona VRML Client such as screen appearance, a renderer mode, and other options.
Help. Lets you view the online help system and general information about Cortona.

To set Cortona preferences, choose Preferences... from the right-button pop-up menu. The ParallelGraphics Cortona Control dialog box is displayed.

Renderer

Allows you to 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.

Renderer options

Wireframe rendering mode. The object appears to be outlined with wires rather than solid.
Dither colors if needed. Controls whether Cortona dithers while rendering. Dithering improves the quality of rendering, but may lower performance.
Motion blur effect. Apply a motion blur effect. This actually makes an image seem a little blurred in motion.
Anti-aliasing. The technique for smoothing out jaggies in showing curves on computer monitor. There are two different modes: Idle-time and Real-time. If the Idle-time option is on, it is applied only for static scene. Whereas selecting Real-time initiates smoothing even in the viewer movement but results in decreasing frame rate.
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.
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.
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.
Phong lighting model. A particular method for computing the apparent color of a face at a particular point. It improves the quality of lighting, but lower performance. Note that this option is available only for R98 Renderer in the Intel Pentium III optimization mode.

Collision detection. By default, Cortona will allow you to pass through objects in your path. To prevent from passing through objects, click Always in the Collision detection box at the Navigation tab.
Background color. You can change a background color of Cortona 3D window: 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.

Using Cortona in HTML Documents

To display a VRML world in a Web browser authors should use the EMBED or OBJECT (supported by Internet Explorer) elements with the proper attributes in an HTML document:

An example of using EMBED

<EMBED SRC="file.wrl"
WIDTH="300"
HEIGHT="300"
PLUGINSPAGE="http://www.parallelgraphics.com/cortona"
VRML_DASHBOARD="FALSE"
VRML_BACKGROUND_COLOR="#000077"
CONTEXTMENU="FALSE"
MASK="0 0, 150 10, 300 0, 290 150, 300 300, 150 290, 0 300, 10 150">

where

SRC specifies the name of the VRML scene to be loaded.
PLUGINSPAGE If the user doesn't have a plug-in installed to handle the defined object data type, then it is possible to guide the user to a different URL (the value of the PLUGINSPAGE attribute) to provide instructions on installing the necessary plug-in module.
VRML_DASHBOARD "TRUE" - turns on horizontal and vertical toolbars; "FALSE" - turns off.
VRML_BACKGROUND_COLOR "#rrggbb" specifies the background color of the 3D window (hexadecimal).
CONTEXTMENU "TRUE" - enables context menu in the 3D window; "FALSE" - disables.
MASK allows to specify non-rectangle clipping region.

See how it works

An example of using OBJECT

<OBJECT
CLASSID="CLSID:86A88967-7A20-11d2-8EDA-00600818EDB1"
WIDTH="300"
HEIGHT="300">
<PARAM NAME="Scene" value="file.wrl">
</OBJECT>

where

CLASSID identifies the Cortona ActiveX control for the browser. The value must be entered exactly as shown.
WIDTH, HEIGHT standard formatting attributes.
Scene specifies the name of the VRML scene to be loaded.

See how it works

See Cortona SDK documentation for details on properties (http://www.parallelgraphics.com/cortonasdk).

Using Component Cortona

Internet Explorer can automatically download Cortona 3.0 if it is not already installed. It gives the opportunity to reduce download size and choose Cortona as VRML viewer despite the fact that the other VRML browser is installed on the user's computer. This technology provides to developers the CAB file for HTML-based Internet installations of Cortona.

An example of using Component Cortona

<OBJECT
CLASSID="CLSID:86A88967-7A20-11d2-8EDA-00600818EDB1"
CODEBASE="http://www.parallelgraphics.com/bin/cortvrml.cab"
WIDTH="300"
HEIGHT="300">
<PARAM NAME="Scene" value="file.wrl">
</OBJECT>

where

CODEBASE identifies the location of the Cortona (CAB file cortvrml.cab, size: 972KB) so that the browser can automatically download it if it is not already installed.
Scene specifies the name of the VRML scene to be loaded.

See "Using Cortona in HTML documents (with examples)" for details on using Cortona Automatic Installation (http://www.parallelgraphics.com/products/cortona/html/).

3D Scene Stereo Viewing

For full screen stereo you need to install the proper hardware: a graphics card powered onboard stereo glasses adapter, stereo glasses that are compatible with this graphics card, and a monitor that can supply at least the 120Hz required for normal stereo mode. The corresponding drivers and utilities (Microsoft DirectX 6 or a later version - this depends on your graphics card) should also be installed in your system.

Go to "Start" on your desktop. Choose Settings -> Control Panel -> Display and configure your system to support stereo in the DirectX VR mode. Set the refresh rate to 120Hz and stereo output format to page-flipping. Before enabling the stereoscopic mode, make sure that your monitor can support the 120Hz mode under the display modes you want to use, for example 640x480x16 bits, 800x600 x16 bits, 1024x768 x16 bits, and so on.

Please note that Cortona supports VR 3D Glasses for 3D scene stereo viewing only in the Full Screen mode. To enter the Cortona Full Screen mode, choose "Full Screen" from the right-button pop-up menu and choose the desired display mode. To close the Full Screen, press ESC or F11.