Real walking in virtual environment for factory planning and evaluation
By: Riadh Dhaoui
Tags: Redirected Walking, VR, Oculus Rift, Immersive Vr, Factory Planning

Andreas Kunz, Markus Zank, Morten Fjeld, Thomas Nescher

A Summary and Evaluation by Riadh Dhaoui

Inventing a new tool for factory planning and assessment based on virtual reality is the main subject of this paper. The aim for such invention is enabling designers, planning professionals, and employees to move natural and free in a virtual factory. Therefore, and as a first step designs have to be checked before anything can be realized.

Nowadays, buildings or manufacturing facilities are designed with specialized design software and Building Information Modeling tools that contribute in evaluating the resulting virtual model. However, with current, mostly desktop-based tools, it still be difficult to evaluate all human factors, taking the example of evaluating physical restrictions for workers. Thus, the main theme of this research is the application of this new system to factory planning and assessment based on VR, which allows designers, planning experts and other workers to walk natural and free in a virtual factory.

Redirected wanking plays an vital role for free walking in virtual design process before anything is built. In fact, costly redesigns at a later stage and failure will be avoided.

At the beginning, this paper introduces the field of Redirected Walking (RDW). Then, and after showing a typical system for unlimited walking in virtual environments, it explains which RDW algorithms can be used for an application in factory planning and evaluation. Besides, it describes the currently available interaction capabilities of the system.

Additionally, the important tools and methods which are used in this research are, firstly, redirection techniques that are not sufficient to be published in large virtual environments. Moreover, a control algorithm or RDW controller is needed to decide which redirection technique can be applied and with which parameters. As example is the RDW controller that determines that curvature gain must be applied to redirect the user clockwise in the right space. In fact, the so-called steering-to-destination RDW Controllers are simple heuristic controllers that constantly redirect a user to a fixed point in real space or in orbit.

On the other side, not using architectural illusions and blindness change would lead to wrong times when walking over a track. As well as, rotation gain is very important in this research as it is responsible for the scaling of the user´s rotational movements like head turns or full body turns. What’s more, reset techniques were also applied in this research because they essentially stop a user and instruct him to perform some activity so that he can be reoriented or repositioned.

Furthermore, translation gain is the Scaling of the translational movement of the user, which determines the speed of the user in the virtual environment either increased or decreased. Not only the redirected techniques are applied in this research but also Mujber et al. determined that fully immersive VR is very useful for planning and designing in industry. Though, such of an immersive VR system were very expensive and they could not be used to real business processes.

The VR system which is presented in this paper, is based on RDW which reduces obviously these costs significantly. As a used hardware in this research are Oculus DK HMD 960x1080 resolution per eye and a backpack to carry a notebook. In order to track the user’s point of view in real space, an Intersense IS-1200 6 degrees of freedom tracking system [29] (180 Hz update rate, 6 ms latency) is attached to the HMD.

Plus, the notebook processes the tracking data from the locator and render the scene as it supplies all hardware components. Hence, the VR system is wireless gives the ability to the user to walk freely in a real room. The size of the used tracking room is about 12 mx 6 m. For this paper, the Unity3D 2 game engine is used as a software which is runs an RDW controller, applies redirection, and forwards this data to a rendering engine.



There are also other alternative metaphors for navigation which are combined with RDW. In the one hand, gradual translation can be done with objects that carry a user in the virtual environment like escalators. In other hand, the mouse, joystick, or keyboard are most known navigation metaphors for desktop systems which are based on flying techniques. In this case, the user uses manual interaction to shift the focus through the virtual environment. For immersive VR strong visual acceleration or movement combined with no real Physical acceleration or movement is a cause of simulator disease.

In order to reduce the effect of simulator, the users get sick should at least be equipped with a movable reference system. For example, to fly through a scene, a user should be forced to use a “flying carpet” or a virtual car. Then, the user can move on the carpet and look around for example, when maneuvering the carpet with a joystick. Moreover, for quickly moving from one discrete location to another are teleporting methods very useful metaphors. For example, a “radiant” metaphor smooth the virtual scene to black, places the user to a new location in the virtual factory and fane towards the virtual scene. Radiating portals can be also appears when the user manually selects his destination in portal mode and as soon as it crosses the portal, it is teleported at the new location. As a result, teleportation can lead to a simulator sickness. Then, teleportation can be combined with redirection by dynamically placing the portal to a smart place.

This paper reveals the results which are obtained by implementing the hardware oculus DK2 HMD together with the visualization software Unity3D game engine, steering algorithms and the RDW controller for suitable redirection technique depending on the current position of the user in the real and virtual environment. Thence, this system gives designers, planning experts, and work-forces the ability to walk naturally and freely within a virtual factory before anything is built. Then, with this system users can walk freely through virtual factories even if they are physically located in a much smaller room. Besides, other methods confirm that users are able to travel over large distances in virtual factory when walking has in this case no sense. Lastly, A few methods have been shown how users can record or comment features in the virtual factory for later discussions or later visits.

This work impacts my research in two directions. Firstly, the use of the Meaningful combination of methods and tools Hardware and software which are selected with Precision and applied in the right situation. Secondly, in this work the searchers don’t solve the problem of the collective walk, when multiple users visit the same virtual factory and walk through it together.