Virtual reality applications seek to fully immerse participants into their virtual world experien... more Virtual reality applications seek to fully immerse participants into their virtual world experience. The investiga- tion of how stimuli on the different senses influence the users is therefore crucial. As navigation is one of the most ubiquitous tasks in virtual environments, studying the influence of haptics on user presence is a necessity for future applications. This work presents an empirical
Applying force feedback applications in a therapy environment allows the patient to practice in a... more Applying force feedback applications in a therapy environment allows the patient to practice in a more independent manner, with less intervention of the therapist. Currently however, high-end devices such as the Phantom or the HapticMaster are far too expensive to provide a device per patient. Recently Novint launched a low-cost haptic device for the gaming market: the Falcon. In this paper we report on an experiment that we conducted in order to compare the Falcon and the Phantom, based on a Fitts' law targeting task. We deduced physical parameters such as inertia and damping, which were found to be different for the devices. Although from a velocity analysis these differences can be clearly seen, it turns out that the influence of different forces does not show significant differences when taking completion time and error rate into account. From a subjective experiment, we can learn that users allow the Falcon to produce slightly higher forces than the Phantom before forces are judged as too strong.
Besides realistic haptic rendering of objects, haptic feedback can also be used to provide an abs... more Besides realistic haptic rendering of objects, haptic feedback can also be used to provide an abstract feedback channel. This can either be realised by a tactile or a force feedback stimulus. When using forces, care has to be taken that the user's performance is not influenced in a negative way. However, as it is not obvious to determine a suitable force, and currently not many guidelines exist. Therefore, in this paper we investigate the influence on some important parameters that define a force (shape, duration and amplitude). In order to compare different forces, we propose to use the definite integral (Force Integral, FI) which combines the considered parameters. From the conducted experiment we learn that the FI can be used (within bounds) to make an estimation of the result of the force. Besides this, we also found that above a given FI value, the user's performance degrades significantly.
Only a few guidelines exist for defining the force properties in a haptic interface; as a consequ... more Only a few guidelines exist for defining the force properties in a haptic interface; as a consequence, they are mostly determined in an ad-hoc manner. We investigate how the user's performance changes during target acquisition when increasing force amplitudes are applied. Using a simple multidirectional point-select task, forces with variable amplitudes are applied to the user while traversing from one target to the other. We find that the user's performance suddenly degrades significantly, rather than decreasing progressively. This finding may be important for defining guidelines which forces may and may not be applied to a user in order to allow the haptic feedback to improve, rather than deteriorate the user's performance.
Designing and exploring multimodal interaction techniques, such as those used in virtual environm... more Designing and exploring multimodal interaction techniques, such as those used in virtual environments, can be facilitated by using high-level notations. Besides task modelling, notations have been introduced at the dialog level such as our notation NiMMiT. For advanced interaction techniques, there is not yet an established approach to decide when to stop detailing the task model and continue modelling at
In order to optimise functional performance and quality of life of multiple sclerosis (MS) patien... more In order to optimise functional performance and quality of life of multiple sclerosis (MS) patients, it is important to provide them with an appropriate rehabilitation program. Especially, during the later stages of the disease, exercising the upper limb is needed to maximise functionality in daily life. In order to provide patients with an individual training program, adapted to their possibilities and to assess their progress, we have been investigating the feasibility of using force feedback in combination with a virtual environment. However, the training tasks given to patients must be motivating for them to continue the rehabilitation program for a longer period. To increase this motivation, we have developed a collaborative rehabilitation game. In this game, the patient has to make training-specific movements in order to successfully complete the game. This game can, however, not be played alone. In fact, only through collaboration of the patient, using the HapticMaster, and t...
Object selection is a primary interaction technique which must be supported by any interactive th... more Object selection is a primary interaction technique which must be supported by any interactive three-dimensional virtual reality application. Although numerous techniques exist, few have been designed to support the selection of objects in dense target environments, or the selection of objects which are occluded from the user's viewpoint. There is, thus, a limited understanding on how these important factors will
Abstract. Designers and developers of virtual environments have to consider that providing adapta... more Abstract. Designers and developers of virtual environments have to consider that providing adaptation in virtual environments is important to comply with users' different characteristics. Due to the many possibil-ities of adaptation that a designer can think of, it is necessary to support the ...
In order to support context-dependency in model-based development, three components need to be re... more In order to support context-dependency in model-based development, three components need to be realised: Context Detection, Context Switching and Context Handling. Context detection is the process for detecting changes in context, while context switching brings the system in the new state that needs to be supported. Finally, context handling adapts the interaction possibilities to the current context. In this paper we discuss an approach for context detection and switching for virtual environments that is based on the Event-Condition-Action paradigm. Both context detection and switching are split-up and supported by our graphical notation for the design of multimodal interaction techniques. The main advantage of this approach is that we provide the designer with a flexible context system, supported by scalable diagrams.
2012 IEEE Symposium on 3D User Interfaces (3DUI), 2012
Wayfinding inside a virtual environment is a cognitive process during navigation. Normally the us... more Wayfinding inside a virtual environment is a cognitive process during navigation. Normally the user inside the virtual environment has to rely on himself and different cues such as waypoints to improve his knowledge with regard to his surroundings. In this paper we will present our solution for the 3DUI Contest 2012: Heat-MeUP, a 3DUI serious game to explore collaborative alternatives, in which a partner is responsible for providing wayfinding cues. The game is set in a multi-storey building where several fires and gas leaks occur and a firefighter has to overcome several challenges, guided by a fire chief.
Using semantic information when interacting in a virtual environ- ment is still not a commonly us... more Using semantic information when interacting in a virtual environ- ment is still not a commonly used practice. In the rare cases where it is applied with success, the implementation however is mostly in an ad-hoc manner, incorporating the semantic information in the programming code so that it can be used in the interaction. In this paper, we discuss a possible
2011 IEEE Symposium on 3D User Interfaces (3DUI), 2011
Not many virtual 3D puzzle applications have been researched. We present a solution using tangibl... more Not many virtual 3D puzzle applications have been researched. We present a solution using tangible objects and a reach-in set-up. The user can solve a puzzle using natural and tangible interaction. To provide realistic interaction, the usage of buttons was avoided by design. In a user experiment the solution proved to be natural and intuitive.
Abstract. Whether a user interface is intuitive depends amongst oth-ers on (multimodal) feedback.... more Abstract. Whether a user interface is intuitive depends amongst oth-ers on (multimodal) feedback. The addition of multimodal feedback can certainly improve interaction in Virtual Environments as it increases the bandwidth to the user. One of the most common tasks in Virtual Envi- ...
Proceedings of the 2007 workshop on Multimodal interfaces in semantic interaction - WMISI '07, 2007
The integration of semantic information in virtual environment interaction is mostly still ad-hoc... more The integration of semantic information in virtual environment interaction is mostly still ad-hoc. The system is usually designed in such a way that the design of the framework incorporates the semantic information which then can be used to utilise these semantics during interaction. We introduce a model-based user interface approach which introduces semantic information, represented using ontologies, during the modelling
ABSTRACT The creation of virtual environments is often a lengthy and expensive process. Especiall... more ABSTRACT The creation of virtual environments is often a lengthy and expensive process. Especially defining the interaction dialog between the user and the environment is a difficult task, as the communication is often multimodal by nature. In this chapter, we elaborate on an approach which facilitates the development of this kind of user interfaces. In particular, we propose a Model-Based User Interface Design process (MBUID), in which the interface is defined by means of high level notations, rather than by writing low level programming code. The approach lifts the design to a higher level of abstraction, resulting in a shortened development cycle leaving the opportunity for creating intermediate prototypes and user evaluation, ultimately resulting in better and cheaper virtual environment interfaces.
Proceedings of the 10th international conference on Multimodal interfaces - IMCI '08, 2008
Despite of decades of research, creating intuitive and easy to learn interfaces for 3D virtual en... more Despite of decades of research, creating intuitive and easy to learn interfaces for 3D virtual environments (VE) is still not obvious, requiring VE specialists to define, implement and evaluate solutions in an iterative way, often using lowlevel programming code. Moreover, quite frequently the interaction with the virtual environment may also vary dependent on the context in which it is applied, such as the available hardware setup, user experience, or the pose of the user (e.g. sitting or standing). Lacking other tools, the context-awareness of an application is usually implemented in an ad-hoc manner, using low-level programming, as well. This may result in code that is difficult and expensive to maintain. One possible approach to facilitate the process of creating these highly interactive user interfaces is by adopting a model-based user interface design. This lifts the creation of a user interface to a higher level allowing the designer to reason more in terms of high-level concepts, rather than writing programming code. In this paper, we adopt a model-based user interface design (MBUID) process for the creation of VEs, and explain how a context system using an Event-Condition-Action paradigm is added. We illustrate our approach by means of a case study.
Speech interfaces are becoming more and more popular as a means to interact with virtual environm... more Speech interfaces are becoming more and more popular as a means to interact with virtual environments but the development and integration of these interfaces is usually still ad-hoc, especially the speech grammar creation of the speech interface is a process commonly performed by hand. In this paper, we introduce an approach to automatically generate a speech grammar which is generated using semantic information. The semantic information is represented through ontologies and gathered from the conceptual modelling phase of the virtual environment application. The utterances of the user will be resolved using queries onto these ontologies such that the meaning of the utterance can be resolved. For validation purposes we augmented a city park designer with our approach. Informal tests validate our approach, because they reveal that users mainly use words represented in the semantic data, and therefore also words which are incorporated in the automatically generated speech grammar.
Virtual reality applications seek to fully immerse participants into their virtual world experien... more Virtual reality applications seek to fully immerse participants into their virtual world experience. The investiga- tion of how stimuli on the different senses influence the users is therefore crucial. As navigation is one of the most ubiquitous tasks in virtual environments, studying the influence of haptics on user presence is a necessity for future applications. This work presents an empirical study on the role of haptics during travel in a desktop virtual envi- ronment. Three techniques were compared in respect to task performance, perceived task performance, perceived presence and mental and physical workload. While our results indicate that haptics has a positive influence on participant's perceived presence and performance, his total workload remains constant. Furthermore, we show that these findings apply to both experienced and unexperienced virtual environment users.
International Journal of Human-Computer Studies, 2009
Object selection is a primary interaction technique which must be supported by any interactive th... more Object selection is a primary interaction technique which must be supported by any interactive three-dimensional virtual reality application. Although numerous techniques exist, few have been designed to support the selection of objects in dense target environments, or the selection of objects which are occluded from the user's viewpoint. There is, thus, a limited understanding on how these important factors will affect selection performance. In this paper, we present a set of design guidelines and strategies to aid the development of selection techniques which can compensate for environment density and target visibility. Based on these guidelines, we present new forms of the ray casting and bubble cursor selection techniques, which are augmented with visual, audio, and haptic feedback, to support selection within dense and occluded 3D target environments. We perform a series of experiments to evaluate these new techniques, varying both the environment density and target visibility. The results provide an initial understanding of how these factors affect selection performance. Furthermore, the results showed that our new techniques adequately allowed users to select targets which were not visible from their initial viewpoint. The audio and haptic feedback did not provide significant improvements, and our analysis indicated that our introduced visual feedback played the most critical role in aiding the selection task. r
Virtual reality applications seek to fully immerse participants into their virtual world experien... more Virtual reality applications seek to fully immerse participants into their virtual world experience. The investiga- tion of how stimuli on the different senses influence the users is therefore crucial. As navigation is one of the most ubiquitous tasks in virtual environments, studying the influence of haptics on user presence is a necessity for future applications. This work presents an empirical
Applying force feedback applications in a therapy environment allows the patient to practice in a... more Applying force feedback applications in a therapy environment allows the patient to practice in a more independent manner, with less intervention of the therapist. Currently however, high-end devices such as the Phantom or the HapticMaster are far too expensive to provide a device per patient. Recently Novint launched a low-cost haptic device for the gaming market: the Falcon. In this paper we report on an experiment that we conducted in order to compare the Falcon and the Phantom, based on a Fitts' law targeting task. We deduced physical parameters such as inertia and damping, which were found to be different for the devices. Although from a velocity analysis these differences can be clearly seen, it turns out that the influence of different forces does not show significant differences when taking completion time and error rate into account. From a subjective experiment, we can learn that users allow the Falcon to produce slightly higher forces than the Phantom before forces are judged as too strong.
Besides realistic haptic rendering of objects, haptic feedback can also be used to provide an abs... more Besides realistic haptic rendering of objects, haptic feedback can also be used to provide an abstract feedback channel. This can either be realised by a tactile or a force feedback stimulus. When using forces, care has to be taken that the user's performance is not influenced in a negative way. However, as it is not obvious to determine a suitable force, and currently not many guidelines exist. Therefore, in this paper we investigate the influence on some important parameters that define a force (shape, duration and amplitude). In order to compare different forces, we propose to use the definite integral (Force Integral, FI) which combines the considered parameters. From the conducted experiment we learn that the FI can be used (within bounds) to make an estimation of the result of the force. Besides this, we also found that above a given FI value, the user's performance degrades significantly.
Only a few guidelines exist for defining the force properties in a haptic interface; as a consequ... more Only a few guidelines exist for defining the force properties in a haptic interface; as a consequence, they are mostly determined in an ad-hoc manner. We investigate how the user's performance changes during target acquisition when increasing force amplitudes are applied. Using a simple multidirectional point-select task, forces with variable amplitudes are applied to the user while traversing from one target to the other. We find that the user's performance suddenly degrades significantly, rather than decreasing progressively. This finding may be important for defining guidelines which forces may and may not be applied to a user in order to allow the haptic feedback to improve, rather than deteriorate the user's performance.
Designing and exploring multimodal interaction techniques, such as those used in virtual environm... more Designing and exploring multimodal interaction techniques, such as those used in virtual environments, can be facilitated by using high-level notations. Besides task modelling, notations have been introduced at the dialog level such as our notation NiMMiT. For advanced interaction techniques, there is not yet an established approach to decide when to stop detailing the task model and continue modelling at
In order to optimise functional performance and quality of life of multiple sclerosis (MS) patien... more In order to optimise functional performance and quality of life of multiple sclerosis (MS) patients, it is important to provide them with an appropriate rehabilitation program. Especially, during the later stages of the disease, exercising the upper limb is needed to maximise functionality in daily life. In order to provide patients with an individual training program, adapted to their possibilities and to assess their progress, we have been investigating the feasibility of using force feedback in combination with a virtual environment. However, the training tasks given to patients must be motivating for them to continue the rehabilitation program for a longer period. To increase this motivation, we have developed a collaborative rehabilitation game. In this game, the patient has to make training-specific movements in order to successfully complete the game. This game can, however, not be played alone. In fact, only through collaboration of the patient, using the HapticMaster, and t...
Object selection is a primary interaction technique which must be supported by any interactive th... more Object selection is a primary interaction technique which must be supported by any interactive three-dimensional virtual reality application. Although numerous techniques exist, few have been designed to support the selection of objects in dense target environments, or the selection of objects which are occluded from the user's viewpoint. There is, thus, a limited understanding on how these important factors will
Abstract. Designers and developers of virtual environments have to consider that providing adapta... more Abstract. Designers and developers of virtual environments have to consider that providing adaptation in virtual environments is important to comply with users' different characteristics. Due to the many possibil-ities of adaptation that a designer can think of, it is necessary to support the ...
In order to support context-dependency in model-based development, three components need to be re... more In order to support context-dependency in model-based development, three components need to be realised: Context Detection, Context Switching and Context Handling. Context detection is the process for detecting changes in context, while context switching brings the system in the new state that needs to be supported. Finally, context handling adapts the interaction possibilities to the current context. In this paper we discuss an approach for context detection and switching for virtual environments that is based on the Event-Condition-Action paradigm. Both context detection and switching are split-up and supported by our graphical notation for the design of multimodal interaction techniques. The main advantage of this approach is that we provide the designer with a flexible context system, supported by scalable diagrams.
2012 IEEE Symposium on 3D User Interfaces (3DUI), 2012
Wayfinding inside a virtual environment is a cognitive process during navigation. Normally the us... more Wayfinding inside a virtual environment is a cognitive process during navigation. Normally the user inside the virtual environment has to rely on himself and different cues such as waypoints to improve his knowledge with regard to his surroundings. In this paper we will present our solution for the 3DUI Contest 2012: Heat-MeUP, a 3DUI serious game to explore collaborative alternatives, in which a partner is responsible for providing wayfinding cues. The game is set in a multi-storey building where several fires and gas leaks occur and a firefighter has to overcome several challenges, guided by a fire chief.
Using semantic information when interacting in a virtual environ- ment is still not a commonly us... more Using semantic information when interacting in a virtual environ- ment is still not a commonly used practice. In the rare cases where it is applied with success, the implementation however is mostly in an ad-hoc manner, incorporating the semantic information in the programming code so that it can be used in the interaction. In this paper, we discuss a possible
2011 IEEE Symposium on 3D User Interfaces (3DUI), 2011
Not many virtual 3D puzzle applications have been researched. We present a solution using tangibl... more Not many virtual 3D puzzle applications have been researched. We present a solution using tangible objects and a reach-in set-up. The user can solve a puzzle using natural and tangible interaction. To provide realistic interaction, the usage of buttons was avoided by design. In a user experiment the solution proved to be natural and intuitive.
Abstract. Whether a user interface is intuitive depends amongst oth-ers on (multimodal) feedback.... more Abstract. Whether a user interface is intuitive depends amongst oth-ers on (multimodal) feedback. The addition of multimodal feedback can certainly improve interaction in Virtual Environments as it increases the bandwidth to the user. One of the most common tasks in Virtual Envi- ...
Proceedings of the 2007 workshop on Multimodal interfaces in semantic interaction - WMISI '07, 2007
The integration of semantic information in virtual environment interaction is mostly still ad-hoc... more The integration of semantic information in virtual environment interaction is mostly still ad-hoc. The system is usually designed in such a way that the design of the framework incorporates the semantic information which then can be used to utilise these semantics during interaction. We introduce a model-based user interface approach which introduces semantic information, represented using ontologies, during the modelling
ABSTRACT The creation of virtual environments is often a lengthy and expensive process. Especiall... more ABSTRACT The creation of virtual environments is often a lengthy and expensive process. Especially defining the interaction dialog between the user and the environment is a difficult task, as the communication is often multimodal by nature. In this chapter, we elaborate on an approach which facilitates the development of this kind of user interfaces. In particular, we propose a Model-Based User Interface Design process (MBUID), in which the interface is defined by means of high level notations, rather than by writing low level programming code. The approach lifts the design to a higher level of abstraction, resulting in a shortened development cycle leaving the opportunity for creating intermediate prototypes and user evaluation, ultimately resulting in better and cheaper virtual environment interfaces.
Proceedings of the 10th international conference on Multimodal interfaces - IMCI '08, 2008
Despite of decades of research, creating intuitive and easy to learn interfaces for 3D virtual en... more Despite of decades of research, creating intuitive and easy to learn interfaces for 3D virtual environments (VE) is still not obvious, requiring VE specialists to define, implement and evaluate solutions in an iterative way, often using lowlevel programming code. Moreover, quite frequently the interaction with the virtual environment may also vary dependent on the context in which it is applied, such as the available hardware setup, user experience, or the pose of the user (e.g. sitting or standing). Lacking other tools, the context-awareness of an application is usually implemented in an ad-hoc manner, using low-level programming, as well. This may result in code that is difficult and expensive to maintain. One possible approach to facilitate the process of creating these highly interactive user interfaces is by adopting a model-based user interface design. This lifts the creation of a user interface to a higher level allowing the designer to reason more in terms of high-level concepts, rather than writing programming code. In this paper, we adopt a model-based user interface design (MBUID) process for the creation of VEs, and explain how a context system using an Event-Condition-Action paradigm is added. We illustrate our approach by means of a case study.
Speech interfaces are becoming more and more popular as a means to interact with virtual environm... more Speech interfaces are becoming more and more popular as a means to interact with virtual environments but the development and integration of these interfaces is usually still ad-hoc, especially the speech grammar creation of the speech interface is a process commonly performed by hand. In this paper, we introduce an approach to automatically generate a speech grammar which is generated using semantic information. The semantic information is represented through ontologies and gathered from the conceptual modelling phase of the virtual environment application. The utterances of the user will be resolved using queries onto these ontologies such that the meaning of the utterance can be resolved. For validation purposes we augmented a city park designer with our approach. Informal tests validate our approach, because they reveal that users mainly use words represented in the semantic data, and therefore also words which are incorporated in the automatically generated speech grammar.
Virtual reality applications seek to fully immerse participants into their virtual world experien... more Virtual reality applications seek to fully immerse participants into their virtual world experience. The investiga- tion of how stimuli on the different senses influence the users is therefore crucial. As navigation is one of the most ubiquitous tasks in virtual environments, studying the influence of haptics on user presence is a necessity for future applications. This work presents an empirical study on the role of haptics during travel in a desktop virtual envi- ronment. Three techniques were compared in respect to task performance, perceived task performance, perceived presence and mental and physical workload. While our results indicate that haptics has a positive influence on participant's perceived presence and performance, his total workload remains constant. Furthermore, we show that these findings apply to both experienced and unexperienced virtual environment users.
International Journal of Human-Computer Studies, 2009
Object selection is a primary interaction technique which must be supported by any interactive th... more Object selection is a primary interaction technique which must be supported by any interactive three-dimensional virtual reality application. Although numerous techniques exist, few have been designed to support the selection of objects in dense target environments, or the selection of objects which are occluded from the user's viewpoint. There is, thus, a limited understanding on how these important factors will affect selection performance. In this paper, we present a set of design guidelines and strategies to aid the development of selection techniques which can compensate for environment density and target visibility. Based on these guidelines, we present new forms of the ray casting and bubble cursor selection techniques, which are augmented with visual, audio, and haptic feedback, to support selection within dense and occluded 3D target environments. We perform a series of experiments to evaluate these new techniques, varying both the environment density and target visibility. The results provide an initial understanding of how these factors affect selection performance. Furthermore, the results showed that our new techniques adequately allowed users to select targets which were not visible from their initial viewpoint. The audio and haptic feedback did not provide significant improvements, and our analysis indicated that our introduced visual feedback played the most critical role in aiding the selection task. r
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Papers by Lode Vanacken