The PSS Page

The Personal Space Station Page

Ergonomic Desktop Virtual Reality



The driving vision behind the Personal Space Station is a computer generated interactive 3D workspace designed for a user who is studying a three-dimensional structure. Consider the scenario as illustrated in the figure below. On a desktop is a 3D workspace which displays an image of a molecular structure. A comfortably seated head tracked user has a stereoscopic view of the structure. Tangible input devices allow the user to interact with the model of the structure: to change its position, scale, and orientation; to select and edit elements; and to perform measurements within the structure. The visual and interaction spaces co-located; i.e. the structure is percieved in the same physical position as where the user interacts.

Two handed co-located interaction is used to study a molecule. In this example, the molecule is drawn as a ball-stick and solvent surface representations. A cube is used for positioning the molecule, while a pen is used to position and orient a cutting plane through the solvent surface. The cube is held in the non-dominate hand, which acts as a frame of reference for more precise tasks performed by the dominate hand.
Key technical notions in this vision are:

The Personal Space Station

The figure shows a schematic diagram of the PSS prototype implementation. A head tracked user is seated in front of a mirror on which stereoscopic images of the virtual world are displayed. The mirror reflects the display surface of the CRT monitor into a virtual focus plane (VFP) in front of the user. Cameras track all user actions under the monitor. In this way the visual and interaction space coincide: the user reaches under the mirror into the virtual world without obscuring the image or colliding with the monitor.

A schematic diagram (left) and prototype (right) of the PSS.
The mirror can be mounted at different orientations in the chassis. Head tracking is realized by an acoustic tracker or by using two webcams. Input devices equipped with small markers are tracking by two progressive scan cameras. Optical tracking algorithms analyze the camera images to reconstruct the 3D pose of the devices.
The system is responsive. The acoustic tracker tracks the head position at approximately 50 Hz. The optical tracker tracks the devices at approximately 55 Hz. Typical end-to-end latencies of the optical tracker are around 20 ms.

A cube and a pen as tangible input devices (left). The optical tracker reconstructs the pose of a device by searching for marker patterns (right).

In summary, the main advantages of the PSS are:

Sample Applications

Molecular Graphics

still under construction....
Visual Molecular Dynamics (VMD) is a desktop visualization package for interactive visualization of molecular structures such as proteins, nucleic acids and lipids. The package is widely used in research community for the analysis of these structures. VMD has been ported to the PSS.

Two handed PSS-VMD interaction tasks with tangible devices: molecule positioning and measuring distances between atoms (left) and control panel setting (right).
The PSS version of VMD incorporates various novel interface styles that illustrate the power of the PSS: The governing idea of the PSS-VMD user interface is to provide the user with the sensation of "holding a molecule in the hand".

This is joint work with Arjan Kok at TU/eindhoven.

Medical Visualization

still under construction....

Two handed interaction with the visible woman volumetric dataset: freely positioning of a volume (left), positioning a cutting plane (middle) and real time monitoring of anatomical features (right).
Novel interface styles that illustrate the power of the PSS in the area of medical visualization: The governing idea of the PSS user interface for medical visualization is to provide the user with the sensation of "the skull in the hand" metaphor and using this as a reference frame for more precise operations performed with the dominate hand.

This is joint work with Arjan Kok at TU/eindhoven.


still under construction....

A 64 million star point cloud.
The governing idea of the PSS user interface for astronomy is to provide the user with the sensation of "having a galaxy in his/her hand".

This is joint work with Matthias Hopf at University of Stuttgart.

Installed base

PSSs have been installed at various Dutch research institutes: In addition, preperations are underway to install two PSSs at the Department of Radiology, Academic Hospital Maastricht and one PSS at the Swamerdam Institute of Life Sciences, University of Amsterdam for research in cell biology.

Selected publications