Virtual Landscape Design

The Virtual Landscaping Application was designed to show the capabilities of the Studierstube/VT framework and the transparent pen and PIP. This documents gives a simple visual introduction to the use of the application and its features.

Introduction

	The Studierstube/VT framework works with the Virtual Table, a large table-like display device from Barco Inc. Head-tracked stereo projection is combined with transparent tracked input devices. The transparent Personal Interaction Panel (PIP) is a hand-held transparent surface complemented by a pen-like input device for two-handed high-fidelity interaction with the virtual world displayed on the table.
	The image shows the basic setup of the application. The scene shows an island that is to be populated with artifacts - buildings and trees. The PIP shows 2D user interface elements and 3D artifacts, the latter can be placed in the scene via drag and drop. The pen is used to manipulate objects both on the PIP and in the scene. Actions are generally triggered by sticking the pen's tip into the object (there is usually a visual feedback), then pressing the pen to trigger the action - similar to using a mouse in a desktop system.

Basic construction and gardening tools

The pip is organized in multiple layouts of manipulation elements that can be switched by the buttons in the top row - similar to a tabbed dialog box in a desktop application. The tabs are:


	Construction: Building creation and manipulation
	Gardening: Tree creation and manipulation
	Colorizer: Color artifacts
	Fish net: select objects by sweeping with PIP
	Lasso: select object by circling them on PIP
	Context sensitive information display
	Snapshot: 3D scene management with SEAMS

	The exit button ends the application

Some general remarks:

In construction and gardening mode, artifacts are simply created by dragging and dropping them into the scene.
The left slider allows to browse through a selection of buildings or trees, respectively.
Note that artifacts in the scene can be picked up again and repositioned.
A red wireframe bounding box around the object indicates that it is selected. Note that multiple objects can be selected (see below).
The slider on the right scales the selected objects.

The button below the exit button opens and closes a fly-up menu with objects manipulation functions:

Load a landscape from disk
Save a landscape to disk
Delete selected objects
Select all objects
Deselect all objects
Toggle normal selection/extend selection mode. In normal selection, only one object may be selected at any time, but objects can be moved and positioned. In extend selection mode, clicking into an object switches back and forth its selection state, so multiple objects can be selected.

Colorize tool

The colorchanger sheet allows to pick a color using the sliders for red, green and blue. The color can then be assigned to all selected objects by pressing the button to the right of the color field, or to any object directly by clicking it. Note that only originally white parts of objects change color, the other parts color remains unchanged.

Fish Net Tool

	If you have created a large number of artifacts and want to select a large number of them - e. g., all objects on the right - it is inconvenient to select each artifact individually. Instead, you can use the fish net tool to select a large number of atifacts by simply sweeping the PIP through them like a fish net through the sea (see image below).
	All fished artifact is selected, and also appears as a small 3D icon on the pip in the place where it was caught by the PIP's surface.

As this display can be cluttered, the arrange button allows to align the 3D icons in a regular grid on the PIP's surface to gain a better overview. As it happens that an unwanted artifact is caught in the fish net, its selection may be undone by clicking into the 3D icon on the PIP - the 3D icon disappears, and the artifact is unselected.

Lasso tool

Like the fish net tool, the lasso tool allows convenient selection of a cluster of artifacts. Unlike the fish net, the lasso does not require to reach into the scene, but rather selection can be done with a more or less stationary pen and pip. The tool shows how useful the drawing surface of the pip can be. Artifacts are selected by circling them with an outline drawn on the PIP with the pen (with the button pressed).

The objects contained in the outline are selected, and as a visual feedback, small cross hair makers are shown on the PIP in the places where selected artifacts were visible through the PIP. A new selection can easily be started by starting a new outline.

Context sensitive display and selection tool

Much like a the menus and toolbars change in a context sensitive way as the selected object in a desktop application changes, this view displays a few context sensitive elements on the pip as it is moved through the scene. As different artifacts become visible through the scene, the display changes.

More precisely, the object closest to the center of the PIP is selected and its name is displayed on the PIP. Furthermore, the category of the artifact (building, tree) is determined and a bar of context sensitive colorize buttons (yellows for buildings, greens for trees) is offered on the pip. While this is a very simple use of context sensitive views, is intended to demonstrate what may be done with this kind of context sensitive display.

Snapshot tool

Studierstube also allows to use so-called SEAMS (short for Spatially Extended Anchor Mechanism, sometimes also called magic lenses). SEAMS allow to get a view of another scene or world through a window-like surface, or see a different view of the same scene (e. g., X-ray vision). In Studierstube, a SEAM can be associated with the transparent surface of the PIP and thus easily manipulated.

The snapshot tool allows to freeze a particular view of the scene and carry it around on the PIP. The scene as seen through the SEAM is not a picture, but a live 3D scene which may be viewed from any angle and can have live animated content (e. g. you may modify objects in each view). Compare the picture above - showing the view frozen on the PIP - with the two views below after the PIP has been moved and tilted. Note how the same scene can be seen from multiple angles in the images below.

The snapshot tool offers the following control elements:

Freeze scene in a SEAM on the PIP. The scene is associated and can be carried around on the PIP. By releasing this button, the PIP returns to normal view.

Store SEAM (disconnect from PIP). The SEAM floats whereever it is left. A border is added to the free floating SEAM. Modifications made to the scene are no longer reflected in the SEAM; this feature can be used as a storage or history system for 3D scenes.

Pick up SEAM (reconnect to PIP). Pressing this button indicates that a free floating SEAM is to be picked up, i. e. reconnected to the surface of the PIP. The actual pick-up is achieved by sweeping the PIP through a floating SEAM, much like the fish net works. Note that after doing this you may also unfreeze the view. As the scene seen through the SEAM on the PIP may be different to the scene displayed on the table you can compare two scenes in-place by moving the PIP about. In the image below, the large building has been deleted from the scene, so it is only visible partially through the SEAM. This "historical view" is a potentially very useful feature in comparing alternatives in landscape planning.

Transfer scene from PIP to table. The scene on the table is replaced with the scene seen on through the SEAM on the PIP. Thereby a "stored" scene can be restored.

If a scene is picked up again and unlocked, two versions of the same scene can be compared in-place. In the image, the large building is only visible through the SEAM.

Underground cable TV tool

SEAMS are also used in the Landscaping application to provide X-ray vision to look into the ground and wire up houses to cable TV there. Simply turn the PIP around and you see the scene in wireframe, so the ground is visible. There is a grid on the ground, and by clicking and dragging in the ground, you can draw axis-aligned wires on a grid representing underground wiring. By positioning the X-ray SEAM you may work on different portions of the island without ever loosing the overview of the world.

This page is maintained by Dieter Schmalstieg. It was last updated on June 8, 2000.
If you have any comments, please send a message to dieter@cg.tuwien.ac.at.

	Load a landscape from disk
	Save a landscape to disk
	Delete selected objects
	Select all objects
	Deselect all objects
	Toggle normal selection/extend selection mode. In normal selection, only one object may be selected at any time, but objects can be moved and positioned. In extend selection mode, clicking into an object switches back and forth its selection state, so multiple objects can be selected.

	Studierstube also allows to use so-called SEAMS (short for Spatially Extended Anchor Mechanism, sometimes also called magic lenses). SEAMS allow to get a view of another scene or world through a window-like surface, or see a different view of the same scene (e. g., X-ray vision). In Studierstube, a SEAM can be associated with the transparent surface of the PIP and thus easily manipulated.
	The snapshot tool allows to freeze a particular view of the scene and carry it around on the PIP. The scene as seen through the SEAM is not a picture, but a live 3D scene which may be viewed from any angle and can have live animated content (e. g. you may modify objects in each view). Compare the picture above - showing the view frozen on the PIP - with the two views below after the PIP has been moved and tilted. Note how the same scene can be seen from multiple angles in the images below.

	Freeze scene in a SEAM on the PIP. The scene is associated and can be carried around on the PIP. By releasing this button, the PIP returns to normal view.
	Store SEAM (disconnect from PIP). The SEAM floats whereever it is left. A border is added to the free floating SEAM. Modifications made to the scene are no longer reflected in the SEAM; this feature can be used as a storage or history system for 3D scenes.
	Pick up SEAM (reconnect to PIP). Pressing this button indicates that a free floating SEAM is to be picked up, i. e. reconnected to the surface of the PIP. The actual pick-up is achieved by sweeping the PIP through a floating SEAM, much like the fish net works. Note that after doing this you may also unfreeze the view. As the scene seen through the SEAM on the PIP may be different to the scene displayed on the table you can compare two scenes in-place by moving the PIP about. In the image below, the large building has been deleted from the scene, so it is only visible partially through the SEAM. This "historical view" is a potentially very useful feature in comparing alternatives in landscape planning.
	Transfer scene from PIP to table. The scene on the table is replaced with the scene seen on through the SEAM on the PIP. Thereby a "stored" scene can be restored.