Personalization of Virtual Coaching Applications Using ProceduralModeling

Rene Zmugg1,5, Andreas Braun2, Peter Roelofsma3, Wolfgang Thaller1, Lisette Moeskops3, SvenHavemann1, Gabrijela Reljic4 and Dieter W. Fellner1,2,5

1Institute of Computer Graphics and Knowledge Visualization, Graz University of Technology, Graz, Austria,{r.zmugg, w.thaller, s.havemann, d.fellner}@cgv.tugraz.at

2Fraunhofer IGD, TU Darmstadt, Darmstadt, Germany, andreas.braun@igd.fraunhofer.de3Vrije Universiteit, Amsterdam, Netherlands, {p.h.m.p.roelofsma, l.moeskops}@vu.nl

4University of Luxembourg, Luxembourg, Luxembourg, gabrijela.reljic@uni.lu5Fraunhofer Austria, Graz University of Technology, Graz, Austria

Keywords: Virtual Coaching, Procedural Modeling, Intelligent Environments

Abstract: Virtual coaching is an application area that allows individuals to improve existing skills or learn new ones; itranges from simple textual tutoring tools to fully immersive 3D learning situations. The latter aim at improv-ing the learning experience with realistic 3D environments. In highly individual training scenarios it can bebeneficial to provide some level of personalization of the environment. This can be supported using proceduralmodeling that allows to easily modify shape, look and contents of an environment. We present the applica-tion of personalization using procedural modeling in learning applications in the project V2me. This projectcombines virtual and social networks to help senior citizens maintain and create meaningful relationships. Wepresent a system that uses a procedurally generated ambient virtual coaching environment that can be adjustedby training subjects themselves or in collaboration. A small user experience study has been executed that givesfirst insight to the acceptance of such an approach.

1 INTRODUCTION

The usage of virtual coaching has greatly increasedover the last few years, for various reasons. Inmany cases it augments or even replaces traditionalcoaching, in other instances it allows non-typical usergroups to access coaching resources; but most impor-tantly, the demand of individuals for improving theirskill set has increased (Kozak et al., 1993; Rose et al.,2000). Virtual coaching applications have a consider-able diversity, ranging from simple text-based onlinetools to immersive 3D environments that have beenconfirmed to increase various metrics relevant to thelearning process and thus should be the preferred so-lution (Ijsselsteijn et al., 2006). However, the cre-ation of immersive learning environments typicallydemands collaboration between designers of the 3Dworld that may lack knowledge of the learning pro-cess and creators of the coaching tools that might notbe able to design 3D environments. Such collabo-rations increase costs and thus prevent wide-spreadusage of immersive virtual coaching. Another im-portant factor is acceptance of the system, which can

be increased by providing personalization within thetraining environments, e.g. creating the appearanceof their own premises. In this work we provide initialresults on the acceptance of a personalization tool forvirtual coaching system for elderly users.

Procedural modeling uses algorithms to automati-cally generate 3D models from a limited set of high-level instructions. While the initial investments in thetools may be higher, it allows generating further mod-els easily. In coaching applications this means that asingle procedural modeling tool allows the designersto easily and rapidly design new immersive learningenvironments, without requiring advanced knowledgein 3D modeling. It is easy to modify existing proce-dural environments, thus allowing a higher versatilityand adaptation of the model according to the desiresof the user as well as to the current learning situation.

V2me - Virtual Coach reaches out to me (V2me,2013), is a collaborative European research projectthat aims at providing a coaching platform for olderadults that allows them to create and maintain mean-ingful social relations. This improved social connect-edness helps senior citizens to stay active and health-

ier for longer, as loneliness and lack of social ac-tivities is a major contributing factor to depression.Group therapies for teaching friendship skills haveproven efficient in the past (Stevens et al., 2006).However, it is difficult and costly to provide suchmeasures for a larger population. An alternative ap-proach is virtual coaching that is supported by a lim-ited set of technical systems and can be provided toa larger user group at decreased cost. This approachhas been evaluated in V2me. It was selected as a casestudy to evaluate the advantages of the use of proce-durally generated environments, which allow person-alization of the content. These 3D environments aregenerated and personalized through a separate proce-dural scene editor, whose features are illustrated inthis paper. We envision that procedural modeling sys-tems can help designers and care takers to quickly cre-ate environments that closely resemble the actual en-vironment of a system user. Therefore, a combinedsystem is presented that allows swift creation andadaption of rooms through procedural modeling. In asecond step those rooms can personalized by addingfurther items to the environment, adjusting their po-sition and changing color and appearance of specificaspects.

In this paper we present the prototype tools thatare created for this purpose and how they are appliedin V2me. The system for procedural environmentgeneration has been evaluated by social science ex-perts in a mutual workshop with potential users. Wepresent the initial findings of this study with a partic-ular focus on the personalization aspects.

2 RELATED WORK

2.1 Virtual Coaching Applications

Virtual coaches have been in focus of research forseveral decades. Heylen et al. gave an overview ofearly examples (Heylen et al., 2009). The charac-ter “Karin” is a virtual receptionist residing behindthe information desk at the lobby of the Virtual Mu-sic Center (VMC) - a virtual replica of the theatre inEnschede (Nijholt and Hulstijn, 2000). The dialogueskills of Karin are based on an earlier non-embodieddialogue system that interfaces to a database contain-ing the information on the performances in the actualtheatre. A dialogue system allowed people to querythe information about performances and also to or-der tickets. Another example, INES, is an intelligenttutoring system primarily designed to help studentspracticing nursing tasks with a haptic device in a vir-tual environment (Heylen et al., 2005). INES takes

into account elements of the student’s character, hisor her confidence level, and the difficulty of the task.It, moreover, gives appraisal of the student’s actions.

Carcasso proposed a natural human computer in-teraction paradigm for persons with cognitive impair-ments such as Alzheimer’s disease (Carrasco et al.,2008). The paradigm consists of a realistic virtualcharacter, rendered on a television set, playing therole of a virtual personal assistant that shows re-minders, notifications, and performs short dialogueswith the user. In this paradigm, the television remotecontrol is used as a return channel to capture the user’sresponses. Roelofsma and Sevim (Roelofsma and Se-vim, 2012) suggested a framework for virtual coach-ing in changing lifestyles, including the domain of in-trapersonal dilemmas that occur when people makechoices that are in the best interest of themselves atthe moment of choice, but not in the best interestof themselves in the long run. This framework isbased on multiple selves’ theory that proposes a self-perception of various personal roles, such as a plannerand a doer, which might have conflicting intentionsover time. Ortiz et al. performed an empirical studywith older adults and avatars, showing that subjectsfollow instructions better, that they can understand thefacial impressions of an avatar even when having cog-nitive impairments, and that interaction with an emo-tionally responsive avatar was regarded as pleasant(Ortiz et al., 2007). However, the presence had no per-ceptible influence on recall. They suggest that appli-cation of an avatar should depend closely on the spe-cific task. In A2E2 (A2E2, 2013), virtual coaches areconnected to several sensors, which include an activ-ity and a movement sensor, as well as blood pressureand weight sensors. The Virtual Coach interacts withthe elderly persons in real time in their home environ-ment and motivates the elderly to a healthy lifestyle.

2.2 Procedural Modeling

A conventional 3D model consists of geometry datathat describes the shape of objects and their pose (po-sition + orientation) in a 3D scene. By contrast, aprocedural model is a computer program that gener-ates this geometry data on the fly when it is run. Thus,it describes the operations required to create an object.A procedural model can, therefore, describe a wholefamily of objects or scenes.

Procedural modeling is used in various kinds ofapplications. First and foremost, it has become es-sential for content creation for computer games andmotion pictures. Here, huge landscapes and urbanstructures are often needed, and with the ever-growingscale of such projects manual construction is becom-

ing increasingly infeasible. Most notably here isEsri’s City Engine (Esri, 2015), which is used to gen-erate large cities and buildings through split gram-mars (Wonka et al., 2003; Muller et al., 2006; Thalleret al., 2013b; Zmugg et al., 2014).

As for coaching applications, it is important thatthe users remain interested in the system, leading toadaptation and personalization as important factors.Modifications can happen on two levels. First, thecare givers may want to re-use existing environmentsand adapt them to provide the users with new content.And second, users may want to change parts of thedisplayed environment to their personal preferences.A procedural modeling system allows both: Changescan be made at any point of the generated scene with-out much effort. Changes of the environment can alsohappen fully automatically based on different aspects.For example, if there is a procedural model of a bed-room for two people, it can be automatically enlargedto fit for four people.

Procedural models are usually described in somesort of scripting language; but this makes the systemnot very accessible for non-expert users. Therefore,an interface without scripting is necessary. The mod-eling packages Houdini (Side Effects Software, 2015)and Grasshopper (McNeel and Associates, 2015)show a graph-based representation of the proceduralmodel. This graph helps to understand how the modelis built and what dependencies exist without showingthe underlying code. In our system, whose theoreticalfoundations were initially presented by Thaller et al.(Thaller et al., 2013a), neither the code nor the under-lying dataflow graph are shown to the user, but depen-dencies are illustrated by highlighting related parts in3D. Furthermore, hierarchically arranged scenes canbe traversed in an intuitive manner. Our system uses adataflow graph only in the background, which is usedto generate the necessary script code automatically.This happens completely transparent to the user.

3 V2ME AND PERSONALIZEDENVIRONMENTS

V2me is a research project that provides a coach-ing platform for older adults that gives lessons tomaintain or create meaningful relations. It is basedon a specifically designed social network that reducescognitive load during use. Simplified communicationsystems allow the users to interact with their peers andpotential new friends through a virtual friendship en-richment course (Stevens, 2001). In order to increasethe efficiency of these aspects, an immersive VirtualCoach – a 3D character that provides lessons, expert

Figure 1: The Virtual Coach (source: (A2E2, 2013)) in a vir-tual environment created with the editor, which is displayedon the Home Platform.

information and links to different aspects of the sys-tem functionality – resides in the apartments of theusers. The virtual environment of this Virtual Coachshould be adaptive to the current situations, both inregards of user input and expert presets that are storedin the system or updated from a central web serviceregularly. A major requirement for the created toolswas that they have to be used by non-technical per-sonnel to allow independent creation of lessons andenvironments. The system is modular and has threemain components. The Mobile Platform is a portabletablet computer that is used independently by the par-ticipant. It provides the Virtual Coach functionalityas text-and-audio representation and enables interac-tion with other users. The Home Platform is a large-screen PC. It communicates with the server to syn-chronize content and host the 3D representation of theVirtual Coach and environments. The Web Platformis a web-based engine that allows family and friendsto communicate with network participants.

3.1 The Home Platform

The Home Platform visualizes the content createdfrom the procedural descriptions. The generated 3Denvironments are the “home” of the Virtual Coach.The Virtual Coach interacts with the user in the pro-vided environments that can be, for example, a flat(see Figure 1), or a park. The procedural environ-ments are generated with a separate piece of software,the Content Editor, which will be presented in the fol-lowing Section 3.2.

The Home Platform is responsible for augmentingall the actions done on the mobile device. The Mo-bile Platform is able to trigger all animations definedfor the environment in the editor. Facial and bodyanimations and the text-to-speech engine of the Vir-tual Coach can also be triggered independently. Uponcompletion of a task by the user, the Virtual Coachreacts with appropriate animations, such as clapping.

The Home Platform provides an immersive inter-action environment for the users of the system. In-stead of the small screen on the mobile device, thelarger screen provides a more sophisticated form ofinteraction. This enables an engaging learning experi-ence for the user that should result in increased partic-ipation, improved learning speed, uptake and recall.

3.2 The Content Editor

We utilize the procedural modeling approach in theContent Editor, which is used to generate environ-ments for the Home Platform. This editor is basedon the Generative Modeling Language GML (Have-mann, 2005) and uses procedural techniques in var-ious ways to create non-static content that can bepersonalized. These include procedural modeling ofbackdrops, procedural scene graphs, procedural ob-ject and camera animations, and personalization ofparameters and objects.

In combination, these techniques can be used togenerate 3D animated stories that can be personal-ized for individual persons and used to guide, help,and entertain the target group. This system is adaptedfrom one Zmugg et al. presented in the Cultural Her-itage domain (Zmugg et al., 2012a; Zmugg et al.,2012b). The different steps for the generation of pro-cedural environments are discussed in the next sec-tions. For V2me, we have created only a pilot pro-totype of a procedural scene editor; as in many re-search projects, much remains to be done to be pro-duction ready, but the feedback we got confirmed thatthe overall approach is understood and appreciated byour pilot scene production team (see Section 4).

3.2.1 Modeling of Backdrops

Backdrops are the environment where the VirtualCoach and other objects are positioned in (see theflat in Figure 1). Backdrops can be generated interac-tively without any need of scripting. The parametricsystem is based on a set of basic modeling operationsand procedural assets. The modeling operations areinspired by split grammars and feature several opera-tions to partition existing shapes into smaller pieces.Modeling usually proceeds in a coarse to fine manner,meaning that an initial shape is sequentially refinedto achieve the desired result. To remain concise, themodeling operations are not explained individually inthis paper. For a detailed explanation of the modelingoperations we refer to (Zmugg et al., 2012a).

Procedural assets are ready-made parametricmodels. Our system features several libraries whichinclude, for example, windows (like in (Thalleret al., 2013c)), arches, or other architectural elements.

Figure 2: Selected steps from creating a circular buildingusing the procedural modeling engine. First and secondrow: The the wall is subdivided into parts to define the spacefor the parametric arch. Bottom row: Decisions made atthe beginning (number of sides, radius) can still be changedlater on, which allows change and personalization of proce-dural models (Zmugg et al., 2012b).

These models are, however, not static, instead theyprovide parameters to approximate a wide range ofdifferent elements. They, furthermore, adapt their sizedependent on the shape they are inserted into. An ex-ample demonstrating procedural modeling operationsand procedural assets is shown in Figure 2.

3.2.2 Modeling the Scene Hierarchy

After generating and texturing the background, ele-ments can be positioned in it. We use the concept ofprocedural scene graphs, which was proposed in pre-vious work (Zmugg et al., 2012b). A scene graph isa hierarchical structure to describe dependencies be-tween objects in environments. Every object in thescene is represented by a node in the scene graph.Each node (except for the root node) has one parentand an arbitrary number of children. The parent-childrelation propagates all changes made to the parent toall of its descendants. Technically, every node fea-tures a 3D pose transformation (4×3 matrix) that af-fects all its children. As a simple example, imagine avase that is placed on top of a table. Without a scenegraph, moving the table does not move the vase, andvice versa. By using a scene graph, the node repre-senting the vase can be made a child of the node rep-resenting the table, and, therefore, moving the tablemoves the vase too, while the vase, as the child of thetable, can still be freely moved on the table.

The scene graph can be manipulated by the user

Figure 3: A camera flight on the Home Platform visual-ized as a sequence of images. From the view on the VirtualCoach the camera moves to a close-up view on the tabletplaced on the table.

through 3D widgets. This way, e.g. furniture ob-jects, collected from SketchUp 3D Warehouse (Trim-ble Navigation Ltd, 2015), can be arranged in the 3Dscene. Technically speaking, the 3D model of the Vir-tual Coach is part of the scene graph too.

3.2.3 Animating the Scene

Finally, animations can be defined for all the objectsarranged within the scene. To achieve animations,key frames storing position and orientation can be de-fined for any object in the scene graph. During ani-mation, these key frames are interpolated, and can beassigned to specific time slots. For these time slotsspecific avatar animations can be set too. As an ex-ample, the walking animation of the avatar can be ac-tivated while the scene graph node, which containsthe avatar, moves in the scene. The view on the sceneduring these animations is controlled via camera ob-jects that can also be placed on scene graph nodes. Byanimating camera objects, it is easy to produce cam-era view transitions (see Figure 3). The time slots canbe queued and also arranged in parallel to create si-multaneous animation time lines. The environments,together with the defined animation time lines, can beexecuted on demand on the Home Platform.

3.2.4 Personalization of the Scene

The curator mode for this system was introduced inprevious work (Zmugg et al., 2012b) in a CulturalHeritage context. It can be utilized within an AmbientAssisted Living context in a different, but related way.The curator mode was designed to provide a museumcurator with a way to make final changes to the scenelayout. The scene is defined through a scene templatebeforehand. This template encodes everything the cu-rator is allowed to change and possibilities are delib-

Figure 4: Different ways for furniture placement in a livingroom realized through use of the personalization mode.

erately limited so that they are shielded from acciden-tally doing harm to the scene, and to work in a moretargeted and efficient way.

The situation within the V2me system is similar.Caregivers can design environments and the animatedstories within them. Afterwards, the elderly peoplecould use this so-called personalization mode to per-sonalize the environment. For instance, it is possibleto define within the template which parameters canbe edited by the elderly users. Take, for example, themodel from Figure 2. It may be allowed to change theradius of this model freely, but the position and thenumber of segments may be fixed or constrained. An-other feature are the so-called drop targets, which arepositions for additional content. For example, arounda table a set of six drop targets with restricted move-ment capabilities can be placed. The user can thendecide how many (up to six), and which chairs theywant to place around the table. This way, users cancreate entirely different environments based on a sin-gle template, by re-arranging objects and even placingnew objects in the scene, such as pictures on a wall(see Figure 4). For the animations, which tell a storythrough the procedural environment, to remain thesame, the configuration options of story-related ani-mations and objects are not available or are restricted.

3.3 Workflow of Creating andPersonalizing an Environment

To give a concrete example we will briefly outline theworkflow (see Figure 5) of generating a personalizedenvironment using the tools presented. At first, thebasic apartment is created using procedural modeling.This step can be performed either by a designer or bya care taker that has been trained for this task. Thismodel can then be stored as a template and be fur-ther used to create new apartments even quicker. Tocreate such models knowledge of the modeling toolfunctionality is required.

The next steps are to be performed by a care takerthat has knowledge of the user’s environment. First,different details are added to the scene. The next stepis adding furniture objects to the scene, such as chairs,tables, or plants. The 3D model of the Virtual Coachis also placed in the scene. Afterwards, animations of

Figure 5: Workflow of creating and personalizing an envi-ronment.

the before placed objects are defined in the scene. Inthis step, the care taker will define where the avatarshould reside and perform most of his actions. This isuseful, e.g. to have the avatar appear in favorite placesof the user. This increases the feeling of immersionfor the user. Lastly, the care taker will define the cam-era views and transitions to highlight specific parts ofthe scene, or the actions and mimic of the avatar.

The last step is the personalization of the environ-ment that happens in a co-creation step between userand care taker in the personalization mode of the sys-tem. Here, personal items can be placed or wrongassumptions about preferences can be redeemed. Theenvironment is visible to both user and care taker andchanges are immediately represented. The final resultis an environment that closely approximates the ac-tual surroundings without requiring the interventionof seasoned designers in most steps of the process.

4 EVALUATION

The concept for friendship coaching within V2mehas been adapted throughout the runtime of theproject (Muuraiskangas et al., 2012). At the end of theproject, a long term study was conducted with severalusers in the Netherlands. In this scope, we wantedto test various aspects of personalization of the sys-tem and how procedural modeling can contribute tothis task. Interviews were conducted with all partic-ipants, covering the aspects on how the quality of aprocedurally modeled environment is regarded, whatelements are required in the environment, and how theenvironment can be improved.

4.1 Study Design

Three women and four men, ranging from 64 to 77years in age, participated in the long term evaluationof the V2me system. The subjects who participatedwere living independently and alone. Subjects wereselected based on their score on the De Jong GierveldLoneliness Scale (de Jong Gierveld and van Tilburg,2006) (scores should be moderate to high) and on

openness to technology (scores should be high). Sub-jects received an instruction session after the V2mesystem was installed in their homes. This systemsetup included a predefined apartment environmentand stories featuring the Virtual Coach. The func-tionalities of the personalization mode itself have notbeen directly part of this study. The predefined setupwas used to assess the interest of the users in chang-ing and personalizing the environment, hence usingthe personalization mode in the future.

The loneliness intervention lasted for two months.Afterwards, they received the loneliness and open-ness to technology questionnaires again, and a semi-structured interview was held about their experienceswith the Home Platform. In this interview they wereasked questions like what they thought of the HomePlatform and the interior of the dwelling, and whatthey would like to see changed, if they could changeit. Because the participants are usually not used toterms like procedural modeling, these questions hadto be designed properly to assess their interest in per-sonalization features.

4.2 Interview Results

Regarding the quality of procedurally modeled envi-ronments, each participant showed to have their ownpreferences for this. One subject mentioned that “Itsvery beautiful, very well made. (...) I like the in-terior a lot.” and “I love how the parquet has beenmade”. Answering on the question what elements aremissing from the virtual environment the responsesvaried from “the house lacks a lot of stuff” to “itis too crowded”. Asking how the environment canbe improved, some participants would have preferredthe coach to reside in a more comfortable environ-ment. They would “add a couch, a little lamp, so hecan sit down and read.” or conclude that “he needsa stereo set, a TV, and a leather couch.” Or “hecould use a fridge or a TV. Or a stove in his kitchen.”Most participants would have preferred their coach tohave some company, including a female housemate,or pets. Finally one participant wanted more interac-tive elements in the environment, such as “a TV thatshows clips from Youtube or news items.”.

4.3 Discussion

The users were generally happy with the visual qual-ity of the procedurally generated environment and theexisting objects added to it. Therefore, we can as-sume that similar environments can be equally wellreceived. Preference plays a huge part in the ques-tion how comprehensive the provided environment

was perceived. Some users found it to be limited, andwould have preferred additional personal items for thecoach. Providing more objects was the most com-mon suggestion for improvement in the future. Hereit is important to create an interface that enables toaccess this variety in a simple fashion. Additionally,some more interaction for the coach should be added,such as companions in the environment. This is moredifficult to accomplish, however the required anima-tions and models can also be procedurally gener-ated. The final aspect is interactivity, whereas objectsshould link to additional services, such as Youtube orWikipedia. Again, this is interesting to pursue in afuture work by creating a library of web services thatcan be linked to objects in the environment.

All in all, the results indicate that every user hastheir own specific preferences for the design of the en-vironments of the Home Platform, so personalizationis a desirable feature for virtual coaching systems.

5 CONCLUSION

We have presented a system which is capable ofgenerating personalizeable environments for elderlypeople within coaching applications that rely on 3Dcontent. Procedural modeling techniques are uti-lized to generate environments, animations and cam-era flights within an editor, which is designed to beaccessible for non-expert users; so programming isnot necessary to use it. This editor is used within theV2me system to generate environments in which theVirtual Coach is presented and interacts with the user.All defined animations and camera flights can be trig-gered by actions of the user. This in combination withlessons that are designed by professional psycholo-gists is used to tell stories and give tasks to motivatepeople to get involved in social activities again. Af-ter all, the ultimate goal of the project is to stimulatericher real-life social experiences.

All elements positioned in the environments cre-ated by our editor can be repositioned and extendedat any time. In a separate personalization mode, theconfiguration options can be limited, so elderly usersgain more control and are shielded from doing harmby not accessing certain parameters. The results fromthe user study explained in Section 4 show that thereis a big interest in personalization of environments.The answers of the participants indicate that a sin-gle environment is not sufficient because the priori-ties and preferences of the participants differ vastly.This shows that procedural modeling needs to be fa-cilitated so that the wishes of elderly people for virtualcoaching systems can be fulfilled with ease.

First results have shown that our approach is apromising new ICT-based method for bringing careto the homes of the elderly people in a socially mean-ingful way. Especially the flexibility and use of thegeneric aspects of the content editor proved to bepromising for care givers and professionals.

5.1 Limitations and Future Work

The system has not been adapted for usage by the el-derly end users of V2me yet. For the current train-ing applications it was more suitable to have a sys-tem that provides developers of training systems withtools that allow them to create immersive environ-ments. For this a rich set of functions have been de-veloped in collaboration with social scientists. Theenvironments for the user study were created by thisteam. However, with a limited amount of trainingthey should be able to create their own environments.The system is prepared for the environment person-alization. Modifications should be accessible for allusers in an intuitive way. The focus of the prototypeup until now was on functionality rather than usabil-ity. Increasing the usability of the system and make itaccessible for elderly user groups is the most impor-tant step in our future work. We anticipate stimulatingpsychological effects if the user can influence the sur-roundings of the Virtual Coach with no assistance.

Additional improvements and future work for theprototype include a more realistic rendering and awider range of possible objects. We currently workon functions to design also the avatar animations pro-cedurally, so that the animations of the Virtual Coachcan be dynamically adapted, e.g., controlling the levelof smiling, or specifying animations that adapt to dif-ferent chair and table heights. This is indispensablefor more interesting plots and stories.

ACKNOWLEDGEMENTS

This work was supported by the AAL Joint Pro-gramme project V2me (grant no. AAL-2009-2-107).We want to thank all participants of the user studies.

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