Vir tual Try-On

Topics in Realistic, Individualized Dressing in Vir tual Reality

A. Divivier, Dr. R. Trieb1, A. Ebert, Prof. Dr. H. Hagen2, C. Gross, A. Fuhrmann, Dr. V. Luckas, Prof. Dr.-Ing. J.L. Encarnação3, E. Kirchdörfer, M. Rupp, S.

Vieth4, S. Kimmerle, M. Keckeisen, Dr. M. Wacker, Prof. Dr. W. Strasser5, Mirko Sattler, Ralf Sarlette, Prof. Dr. R. Klein6

Abstract

In the course of the project Virtual Try-On new VR technologies have been developed, which

form the basis for a realistic, three dimensional, (real-time) simulation and visualization of

individualized garments put on by virtual counterparts of real customers. To provide this cloning

and dressing of people in VR, a complete process chain is being build up starting with the touch-

less 3-dimensional scanning of the human body up to a photo-realistic 3-dimensional presentation

of the virtual customer dressed in the chosen pieces of clothing. The emerging platform for

interactive selection and configuration of virtual garments, the „virtual shop“, will be accessible in

real fashion boutiques as well as over the internet, thereby supplementing the conventional

distribution channels.

1. Introduction Nowadays, consumers with their increasing desire for individuality make high demands within the services sector. Especially, people want to get a good value easily almost at any time and at any place while claiming a wide range of goods, a high degree of individuality as well as quality and service at the highest level. Handling such immense demands will only be possible, if new fundamental technologies for the presentation, selection and “ try out” of products will be developed in order to supplement the classical selling process.

In particular, in the garment field, the virtualization of familiar paradigms (including a virtual try-on) leads to the creation of virtual shop environments (at the point-of-sales or in the internet) which, for the first time, allow offering a wide range of individualized clothing while additionally enhancing shopping experience and customer support.

Nevertheless, previous approaches within this area have not been very successful. But why ? One of the fundamental reasons for the missing success and acceptance of such systems is caused by the lack of identification of the customer with his / her virtual counterpart.

1 Human Solutions GmbH, Europaallee 10, D-67657 Kaiserslautern, Germany

2 IVS, DFKI GmbH, Erwin-Schrödinger-Str. 57, D-67663 Kaiserslautern, Germany

3 FHG/IGD, Fraunhoferstraße 5, D-64283 Darmstadt, Germany

4 Hohenstein Institute for Clothing Physiology, Schloss Hohenstein, D-74357 Bönnigheim, Germany

5 WSI/GRIS, University of Tübingen, Germany, Sand 14, D-72076 Tübingen, Germany

6 Institute of Computer Science II, University of Bonn, Römerstr. 164, D-53117 Bonn, Germany

Currently, most implementations either incorporate pure, two dimensional silhouettes or oversimplified 3d computer-based mannequins, so that the customer will hardly be able to recognize himself / herself. Furthermore, at present, the typical visualization and simulation of garments is not giving any meaningful feedback of the “ look and feel” of the selected cloth. Particularly, garments are rendered independent of the customer’s size, i.e. they always seem to fit. Therefore, no real decision support is given to the customer. Questions like “How does the garment really look like?” , “Does it look good, when I’m wearing the cloth ?“ , can not be answered as well as concerns related to fit and sizing can not be resolved.

In particular, in the context of online shopping, after receiving the ordered garments customers often are disappointed or unsatisfied. This, in turn, leads to high product return rates as well as future indecision to purchase garments over the internet.

Therefore, the goals defined within the Virtual Try-On project aim at an optimal support of the customer in decision making and thus to minimize time and costs for manufacturers and retailers.

2. Vir tual Try-On In the course of the project Virtual Try-On innovative VR technologies have been developed, which form the basis for a realistic, three-dimensional, (real-time) simulation and visualization of individual customers and garments. Utilizing these VR techniques an integrated virtual shop infrastructure is provided, which facilitates the presentation and trade of individualized garments at the point-of-sales and soon over the internet. Instead of replacing the current shopping experience (e.g. really touching garments and materials), Virtual Try-On, in fact, aims at enhancing customer support and decision making through extending corresponding customer services.

The following scenario describes a typical way a customer will experience the VTO shopping environment at the point of sales.

Vir tual Try-On scenar io at the point-of-sales

A customer decides to buy new garments in a fashion boutique, supplying the Virtual Try-On cloning and dressing service. If not done already, his / her body surface will have to be scanned (by 3d laser scanner) in order to create the customer’s digital twin. Henceforth, this virtual avatar will be representating the customer within the virtual try-on application, also serving as the basis for capturing necessary information (i.e. body dimensions and feature points) with respect to the production and / or simulation of garment in relation to the virtual human body. Therefore, additional scans will only be necessary in case the customers body shape has changed noticeable.

By browsing through an interactive, virtual catalog the customer is able to shortlist interesting pieces of clothing. To support this preselection the desired garments are presented in a (fast) preview mode, already showing his / her digital twin wearing the clothes in the chosen colors and materials. Although, thereby, the customer gets a first impression of how the garments would look like when he / she is wearing it, this preview does not provide enough information regarding sizing and fitting.

Therefore, in case the customer wants to have a detailed look at a favoured combination of clothes, a virtual construction process is invoked, which based on the cloth data (model type, color, material, configuration) and the given body dimensions will create individual, adapted three-dimensional models of the desired garments. Further processing of the results will dress

the avatar by utilizing extended, physically-based simulation techniques. For presentation purposes a new output device, the virtual mirror, is used, which provides a life-size display of the customers virtual counterpart dressed in the chosen pieces of clothing from arbitrary viewing angles.

Through all this, modifications with respect to size, configuration and color can be tried out virtually within a short amount of time. After finally deciding to purchase the selected clothes an appropriate order will be created automatically and sent to the corresponding manufacturer.

The Virtual Try-On scenario regarding the internet will be implemented similar to the scenario described above. As a matter of course, the customer will have to be scanned in one of the "Virtual Try-On fashion boutiques” , before being able to access the Virtual Try-On services at home. Instead of utilizing a “virtual mirror” output device, simulation results will be displayed on the customer’s local computer screen.

The following sections give a detailed description of essential topics and implementations required to build up the process chain for handling the Virtual Try-On scenarios.

Creating the vir tual customer (Human Solutions GmbH)

The starting point of the cloning and dressing process within Virtual Try-On is the creation of a three-dimensional virtual counterpart of the customer, the so-called customer avatar.

For this purpose, a 3D laser scanner catches touch-less the customers body surface within a few seconds and produces a three-dimensional point cloud consisting of round about 450.000 to 600.000 points. After post - processing (purifying, smoothing, ...), the point cloud is transferred into a smooth, closed polygonal surface. This is achieved by separating the raw scan into approximately cylindrical parts, reconstructing each part into a B-spline surface (NURBS) individually and merging the results into a single coherent mesh again. To further ensure identification with his / her virtual twin, besides the shape of the human body, color images of the body surface are captured during the scanning process. Mapping this texture data onto the triangle mesh created so far leads to the final version of the static customer avatar (see figure 1, middle).

Figure 1: Different stages creating an individual customer avatar : Scanning the customer’s body surface (left). Static avatar (middle). Dynamic avatar (right).

Based on the exact digital representation of the customer, all measurements and characteristic feature points (e.g. ellbow, shoulder, wrist, …), which are necessary for actually producing and simulating garment in relation to the virtual human body, are captured automatically.

Such characteristic feature points are also taken into account while computing an inner model and a corresponding segmentation of the up to now static customer mesh. By applying skin / mesh deformation methods – based on the combination of vertex-blending and bone-blending – the avatar is enabled to execute simple, but typical movements (Walk, Turn around, ..) of a real customer standing in front of a mirror, controlling fit, look and feel (see figure 1, right). Hereby simulation and presentation of virtual garment worn by the customer avatar can be improved leading to a maximum realistic impression.

Interactive individual clothing catalog (DFKI)

After the virtual customers has been created, he / she can select and combine different garments as well as various colors and patterns in an individual 3D catalog. Instead of applying a time-consuming physically-based cloth simulation, clothing models have been generated before by draping real clothing over a dressmaker’s dummy and catching the model geometry through a 3D laser scanning process. This leads to a model of the cloth with absolute realistic wrinkles. In our approach, the desired garments must be scanned in only one basic size – all other sizes will be calculated in the morphing process.

Rule-based Morphing

In contrast to existing morphing techniques (e.g., [LV94]) here an absolute control over the intermediate shapes is required. I.e., it must be assured that the intermediate shape has the exact associated measures of the needed cloth-size and not something that just looks similar. Cloth sizes are usually defined by individual measures like collar size, sleeve length, back width or sleeve circumference. Therefore we have derived a set of rules which describe the individual changes that have to be made by our morphing agent when transforming one size into another. This process is much more complicated than just zooming in and out, because the changes of the single measures are not uniform. As mentioned above only one piece of real garment is needed for the scan process. Therefore, the developed algorithms apply deformation techniques to the shape in order to produce a new size with corresponding measurements. So our approach [EGH03] deforms a shape but morphs between the sizes. In contrast to the well-known interpolation between two shapes we do not produce additional wrinkles for intermediate shapes. Therefore, the computed new size of the garment looks much more realistic than one which would be produced with ordinary morphing techniques. Furthermore, our approach is very flexible and extensible: by adding additional scans of the same garment in other sizes, during the import process the representation which has the most minimal distance regarding the individual measurements can be chosen. Hereby the accuracy is improved going along with higher but tolerable storage requirements.

After computing the needed size of a garment, the virtual dressing of the figurine is done. In the first step, the garments are positioned around the body – a jacket, for example, is fixed at the shoulder area. Due to the fact that people will always differ a little in their posture during the scan process, the algorithm has to correct the position of the arms in a second step. From observing real life configurations it is clear that there are body parts which are totally hidden by the garment. Consequently, these parts can be blended out by just making them invisible during the rendering process. Only the segments that are partly visible (like the lower arm) must be handled during the following collision detection. This process is shown in figure 2.

Figure 2: Virtual Dressing in the clothing catalog.

Retextur ing using cooperative patterns

Our concept [ESD03] is based on the generation and analysis of a colour code (comparable to a 2D barcode) that is printed on the fabric before the cloth is tailored. Here, the colour code defines a discrete coordinate system, which also represents the fabric direction. The wrinkles – or better: the corresponding hidden areas – can be located by detecting missing portions of code in the texture images produced during the scanning process. We are calling this colour-coded pattern a cooperative pattern.

As a coding unit we’ve chosen a square, because a right-angled coordinate system is very suitable for parameterisation. A character of the coding alphabet is formed from one square and its eight neighbours. Thus, each character has a size of 3×3 squares. We are making use of a hierarchical two-level pattern in an applicable size for the wrinkle recognition, which is composed of a lower and an upper level. The lower level consists of a coded sample as described above. Three colours (red, green, and blue) are used for the coding and a fourth colour (white) is used for the separation of the coded parts. The composition of elements of the lower level forms the upper level. With the two-level pattern a rapport is directly given, so a fabric of arbitrary size can be manufactured.

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pattern of cloth

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Figure 3: Composition of the coded pattern.

Figure 4: Individual 3D clothing catalog visualization.

In case the customer wants to have a detailed look at a favoured combination of clothes, a virtual construction and simulation process is invoked, consisting of three basic steps : pre-positioning, pysically-based simulation and high quality visualization.

Geometr ic Pre-Positioning (FHG/IGD)

Virtual Clothing, that comes from CAD Systems used in the apparel industry, is represented by its two-dimensional cloth patterns. There is also information available, how these patterns must be stitched together. Our dressing method consists of two steps: geometric pre-positioning and physically-based cloth simulation. In the pre-positioning step the cloth patterns are positioned automatically around the body segments. These pattern positions serve as initial values for the cloth simulation, where the patterns are sewed together directly onto the human figure and where the final fitting is computed. The main idea of our pre-positioning algorithm (see also [FGLW03] and [GFL03]) is to use developable bounding surfaces for the human body segments, onto which the cloth patterns are positioned. We assume, that the virtual human body is segmented into several body segments. Additionally, we need the positions of some feature points, which mark special positions of the human body.

Figure 5: Bounding cylinders for arms and legs (left). Cloth patterns of a male shirt positioned according to their sewing information (right).

Bounding Surfaces

Figure 5 (left) shows the minimal bounding surfaces for the arms and the legs. We established a mapping between the minimal bounding surfaces and their flattened counterparts. That means, cylinders are mapped into 2D rectangles and cones into 2D circle parts. This mapping allows us to position the cloth patterns in two-dimensional space and to map them back into their final 3D positions around the human body.

Arranging The Patterns

Cloth patterns, which belong to the same body segment, are positioned by using their sewing information: If two cloth patterns must be stitched together, then they are positioned side by side (see Figure 5, right). Then we use the feature points of the human body to move the cloth patterns onto the flattened bounding surface, before we map them into 3D space around the corresponding body segments.

Pre-positioning of Many Pieces of Clothing

When dressing people with many pieces of clothing, a dressing order is required. This dressing order determines for example, whether you like to wear you shirt inside the trousers or outside. It also identifies the sequence under which the cloth patterns are processed in our pre-positioning algorithm. After a cloth pattern has been pre-positioned the corresponding bounding surface is broadened, so that a cloth pattern, which is processed afterwards on the same body segment, encloses the first pattern. We obtain a sequence of bounding surfaces lying one upon the other for every body segment, onto which the several pieces of clothing can be positioned. (See Figure 6).

Figure 6: Simultaneous pre-positioning of trousers, shirt and jacket

Interactive Java-based garment simulation (FHG/IGD)

For the second step of our dressing method we developed a system for interactive animation of cloth. It is implemented in Java and thus can be easily integrated into the envisioned internet scenario. The triangulated cloth patterns serve as a basis for a mass spring system. Since cloth is a very rigid material when stretched, extremely large forces occur in such a system. Several methods have been described in the recent years to solve the underlying differential equations efficiently [BW98], [CK02], [HE01]. We have developed an algorithm which replaces the internal cloth forces by several constraints and therefore can easily take large time steps without much computational overhead [FGL03].

The simulator also has to handle self collisions and collisions between the human body and the cloth. In order to solve these problems efficiently we are testing only particles against the surface of the body and each other. Distances between particles and the human body are rapidly computed with a signed distance field [FSG03].

Figure 7: Simulation of shirt and trouser (left). Interactive changing of sleeve length. The length can be changed with a slider at interactive rates (right).

Technical requirements of textile and clothing (Hohenstein)

One of the main focuses of this research is defining the influencing variables of the relevant material parameters on the clothing simulation or virtualisation. For this, the individual textile material is not merely regarded in isolation; for the first time, the influences arising from the combinations of materials and the different methods of processing used are specifically analysed and described. At the visualisation stage it is important to be able to accurately represent clothing made of the same pattern but which has been processed in different ways. Both individual materials and combinations of materials for the outer fabric, lining and interlining, as well as materials which have been processed differently, are therefore also analysed. To clearly define the material properties, special measuring systems are employed which are used in the textile and clothing sector to assess the processability of materials and to provide a (comparative) assessment of the handle of textile products. On the basis of the following individual tests the calculation for the material simulation are made: bending (flexing resistance), shearing (deformation of the warp and weft threads from the standard 90 degree angle) and the tensile stress-strain value for the material in question.

On the basis of the results of these tests, methods are derived which enable the relevant material parameters to be determined more simply. This creates the basis on which to consider new textile materials and possible ways of processing these for optimal visualisation with minimal additional effort and to make these new materials available for the virtualisation of clothing.

Figure 8: Defining the relevant material parameters (left) and simplified method to group new materials (right)

Another important aspect of the work is defining the influencing variables which result from the correlation between body geometry and pattern section geometry. 2D pattern sections

currently available, which show different types of stitching and different areas of material are generated in the form of DXF files, edited and input in a product database. In addition to the 2D CAD files, information on the sewing of the individual pattern sections, the areas of material and related material parameters, the body reference points, types of stitching, variations in drape and types of fastening are supplied. This additional information is integrated in XML files, which form the basis for the automatic positioning and sewing of the pattern sections on the virtual bodies. It should be borne in mind here that clothing is not intended to replicate the figure exactly, but to flatter the body shape. In order to make it possible to reproduce the aspect of fit on the computer and to place the clothing optimally on the body, the contact points for appropriate clothing are defined in different sizes, graduations in width and cuts as well as for different postures.

Figure 9: Processing the 2D CAD data as a DXF file (left) and integration of the additional information in an XML file (right)

Physically-Based Cloth Simulation in Vir tual Reality (WSI /GRIS)

The physically based cloth simulation is responsible for sewing the pre-positioned garments along the seam lines and for computing the drape of the clothes on the avatar.

Physical Model and Numer ical Solution

To compute realistic animations of clothes, we developed an efficient model based on finite elements for viscoelastic, highly flexible surfaces. It is particularly designed for numerically stiff materials such as textiles because it yields linear equations in each time step and allows fast time stepping in an implicit integration method. This is achieved by reducing the nonlinear elasticity problem to the planar, linear case in each step. With this model, we are able to assemble garments from CAD cloth patterns [WKK+02], seam these together, and animate the cloth in dynamic scenes with any chosen material properties (see figure 10). This results in a physically accurate but also fast simulation. The basic idea in our approach is to use a linear strain formulation and to construct a rotated rest state for each element [EKS03]. The arising ordinary differential equations time are solved by an implicit Euler method.

Textiles show very different physical behavior in weft and warp directions, so we model elastic and viscous material parameters for the two directions independently. Material measurements are carried out with the Kawabata evaluation system for the two Young moduli, the shear modulus and the Poisson number, which controls the transverse contraction. Additionally, the bending moduli describe the curvature elasticity in the weft and warp directions. In order to model the exact hysteresis effects of the corresponding tissue, dynamic material parameters are measured with the Kawabata and Zwick systems.

Figure 10: Starting with the pre-positioned cloth patterns, the draping is simulated.

Collision Detection and Response

Interactions of the textile with itself and other objects play an important role in physically based animation in order to model collisions and friction and to produce realistic behaviour. We use hierarchies of discrete oriented polytopes (k-DOPs, [EKK+01, MKE03]) to approximate the objects of the simulation. As the meshes in cloth simulations deform almost arbitrarily, efficient update mechanisms for the hierarchies are essential. The hierarchies can be built by a top-down splitting method. Figure 11 shows such an 18-DOP-hierarchy for an avatar. The k-DOP hierarchies can be updated efficiently by merging the bounding volumes from bottom to top.

Since self-collisions are crucial for realistic cloth simulation, they must not be neglected by the collision detection and response. We combine the idea of normal cones with the k-DOP hierarchy to estimate the surface curvature for the region covered by a hierarchy node. Thus, parts of the textiles, where self-intersections are impossible due to their low curvature, are identified and skipped during the self-collision test.

The collisions of the detected particles have to be resolved using a collision response scheme. In our system we therefore implemented three different collision response schemes [KKM+03]:

• Constraint based collision response

• Force based collision response

• Iterative impulse based collision response

For most collision cases the constraint based method is used, because it turned out to be exceedingly valuable in order to avoid collisions before they occur and to achieve large time steps.

Figure 11: 18-DOP hierarchy for an avatar.

Figure 12: Interactive manipulation of garments.

Interactive Manipulation of Clothes in Vir tual Reality (WSI /GRIS)

When we try-on real clothes, we frequently adjust the garments on our body manually. To provide an equivalent in a virtual try-on scenario, we developed interaction techniques which allow to select and drag parts of the garments during the physically based simulation [KSF+03, KSW+03, WKS+03]. In our system, this can be accomplished by utilizing Virtual Reality input devices that allow 6 degrees of freedom to select parts of the clothes, or more precisely, vertices of the underlying mesh. The selected points are visualized by small cubes, which can be moved in the scene (see figure 12). The transformations of the selected vertices are then integrated into the simulation as constraints. When the constraints are released, the cloth relaxes due to internal forces and gravity. This technique allows moving the simulated garments into shape, just like a real person does after putting on real clothes. Moreover, it is a basic tool for virtual garment design. In the future, we want to enable a tailor to experiment with different cloth shapes, creases, and seams in Virtual Reality.

High-Quality Visualization (University of Bonn)

Realistic and high quality visualization is essential to provide the „ look & feel“ of cloth, which depends on the material properties of the cloth surface.

The whole visualization is based on the usage of bidirectional texture functions (BTF) as introduced by Dana et al. [DANA99]. A BTF dataset can be interpreted as a set of images of a flat material surface viewed and lit under a discrete set of direction. Therefore, anisotropic reflection properties of the material, subsurface light transport, interreflections, self-shadowing, occlusion and foreshortening are captured and can be reproduced during rendering.

BTF Measurement - Laboratory

A complete measurement laboratory was set up to allow the automatic measurement of reflection properties of flat material samples, as shown in figure 13. It consists of a robot, a

rail system with a moveable 14 Megapixel high-end digital camera and a HMI light source, which simulates the sun emission spectrum. The whole lab is controlled via self-written computer programs.

The VTO textiles were measured out of 81 different viewing directions. For every viewing direction 81 different lighting directions were used resulting in a dataset of 6561 images per sample. Details are described in Sattler et. al [Sattler03].

BTF Measurement - Postprocessing The captured images represent a data amount of 90GB. This amount is reduced by registering only a representative part of the surface and cut out of the corresponding images. To allow the texturing of large objects, the images are made repeatable using blending methods. For further reduction of the data a principal component analysis (PCA) as well as clustered PCA [Müller03] are applied resulting in up to 24MB for a 256x256 Pixel BTF, where the chosen texture size depends on the material structure and quality requirements. This compression allows for fast decompression, advanced multi-texturing algorithms as explained in the rendering part and is therefore especially suitable for rendering.

Besides the measurement of the material samples for the VTO project, several other samples were measured and made publicly available through an internet site (btf.cs.uni-bonn.de ).

Render ing (University of Bonn)

High-quality visualization of the simulated cloth with the measured material surface reflection properties on a “virtual-mirror” is a main goal of the Virtual Try-On project. The rendering is the last part of the process chain; the simulated cloth geometry and the desired material selection besides the measured BTF data serve as input for this part.

Macroscopic self-shadowing

Macroscopic self-shadowing is an important visual clue to recognize the draping of cloth. Therefore, we compute a local shadow value for each vertex of the geometry [Ganster02]. This is done using an hemi-cube approximation of the hemisphere of each vertex, defined by its normal. Rendering this “view” of the vertex, the incoming radiance out of the discretized directions is determined and stored. Interpolating between values of neighboring vertices yields in a smooth result. By now, the geometry could be rendered with simple texturing and correct self-shadowing. To add the material reflection properties the principal components of the BTF data are incorporated.

BTF reconstruction and render ing

Using high-end graphics accelerators and shading language programming the reconstruction of the BTF out of the principal components is possible at interactive frame rates for the whole geometry [Sattler03]. This is done by evaluating the current viewing and lighting direction for each vertex and using precomputed weights. Using multitexturing the appropriate texture for each triangle is computed. To achieve smooth results and avoid edge artifacts blending is used. Comparisons with other rendering methods show the superior quality of PCA based BTF rendering [Meseth03a]. But using more advanced LPCA compression the rendering quality can still be improved [Klein03,Meseth03b].

Figure 13. Laboratory setup.

Compar ison between “ real” and “ vir tual” cloth

The comparison between “ real” and “virtual” cloth shows, that using only point or directional light sources results in a non natural illumination condition. Therefore, we integrated the possibility to use high dynamic range images (HDRI) to allow for a real-world illumination. As explained in the section “Macroscopic Self-Shadowing” , at each vertex the radiance of the incident light from the measured BTF directions is computed and integrated during the BTF reconstruction. To acquire the HDRIs from real world locations, e.g. shops, a portable measurement system was build. The interactive change of viewing positions and HDRIs were integrated in the BTF renderer to allow the customer a high degree of freedom for her/his judgment (see figure 14).

Figure 14. BTF Rendering of different cloth materials in a measured HDRI environment.

The comparison reveals also, that the geometry silhouette is an important visual clue. To incorporate a correct silhouette representation into the rendering the laboratory was enhanced to also acquire the material silhouette and a new rendering technique for experimentally recorded real material silhouettes was developed.

Dynamic geometry

If the avatar pose is changed, e.g. the customer turns around in front of the “virtual mirror” , the cloth geometry changes. Therefore, geometry simulation and lighting computations have to be carried out in real-time. Due to the computational complexity of the draping simulation as well as the lighting simulation an algorithm was developed, that is capable to estimate the cloth geometry together with vertex based shadow information. Based on a statistical evaluation of geometry and shadow information which is precomputed for most postures and typical movements of humans trying on a certain cloth.

Vir tual Shop

The VR techniques that have been developed in the course of the project Virtual Try-On have been incorporated within an virtual shop infrastructure which will be installed at the point-of-sales (cove&co) for evaluation. By providing an additional realisation of an internet related infrastructure, the E-Commerce Shop, we will supplement conventional distribution channels.

Both applications will be based on a common user paradigm, which provides a uniform way of interaction independent from the customers location and access point. Figure 15 shows screenshot of both the virtual shop and E-Commerce Shop, which is currently under construction.

Figure 15: Virtual shop at the point-of-sales (left). E-Commerce-Shop (right).

Vir tual Mir ror

One of the fundamental ideas within the conception of the Virtual Try-On technology chain is to provide a life-size display of the customers virtual counterpart dressed in the chosen pieces of clothing. By incorporating / combining suitable display techniques and hardware, as well as novel cloth rendering techniques we enable the customer to visualize himself / herself wearing a variety of combinations of different garments from different views (see figure 16).

Figure 16 : Virtual Mirror (left). Comparing simulation results with real garments (right)

Thereby, getting an realistic impression of the “ look and feel” of the garment, this kind of presentation will serve as an important decision support, leading to an enhanced shopping experience for the customer.

3. Exper iences, Assessments In the course of the project, up to now, a complete, prototypical integrated shop infrastructure for customized garment retail at the point-of-sales has been developed. A first small collection of pieces of clothing is being supplied by Odermark and Hohenstein. Although, certainly, calculating speed needs to be improved, (latest) evaluations, have proven that (basic) concepts to be competitive / effective. Especially comparisons of real garments with the corresponding simulation results show a high degree of correspondence (see figure 16 left).

Regarding the high quality visualization the project definitely demonstrates the great improvement of the visualization of cloth by using measured reflectance properties of the real world materials. In addition the greatly improved realism of real reflectance properties of the cloth under natural illumination conditions provides the user with a much better “ look & feel” of the material than previous rendering techniques. This way the client can already judge physical material properties based on the visualization. During the project it became clear, that the collection of reflectance properties of the different cloth materials used in the textile industry is a critical part in the whole visualization chain. In the context of the mass market more optimized labs will be necessary to acquire all this data.

4. Realization Potential, Outlook For the first time, Virtual Try-On has developed a complete process chain regarding the photo realistic visualization and simulation of individual customers and garments. Starting with the creation of individual customer avatars, up to a realistic, physically-based simulation of cloth as well as a the life-size presentation of the customers digital twin wearing the selected cloth, is provided.

All members of the project consortium intend to further transfer the gained experiences and the acquired knowledge into products for retail and manufacturing. Here the benefits will mainly include a reduced cost risk (manufacturing on demand), less cost through rapid prototyping capabilities, less storage as well as a closer customer relationship.

Thereby, it will be expected, that technology and ideas developed in the course of the Virtual Try-On project will contribute to the increasing market of individualized products within the area of garments.

Last but not least it should be mentioned that based on the outstanding visualization results achieved in this project also further applications of this technology in the area of the automotive industry and architecture were initiated.

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2002, 2002.

[GFL03] Gross, C., Fuhrmann, A., and Luckas, V. (2003). Automatic pre-positioning of virtual clothing. In Proceedings of the Spring Conference on Computer Graphics, pages 113–122.

[Hauth02] M. Hauth, O. Etzmuss, B. Eberhardt, R. Klein, R. Sarlette, M. Sattler, K. Daubert, J. Kautz,

Cloth Animation and Rendering, Eurographics 2002, 2002.

[HE01] Hauth, M. and Etzmuß, O. (2001). A high performance solver for the animation of deformable objects

[KKM+03] S. Kimmerle, M. Keckeisen, J. Mezger, M. Wacker, TüTex: A Cloth Modelling System for

Virtual Humans, in: Proceedings of 3D Modelling 2003.

[Klein03] R. Klein, J. Meseth, G. Müller, R. Sarlette, M. Guthe, Á. Balázs, RealReflect - Real-time

Visualization of Complex Reflectance Behaviour in Virtual Protoyping, ACM proceedings

of Eurographics 2003 Industrial and Project Presentations, 2003.

[KSF+03] M. Keckeisen, S. L. Stoev, M. Feurer and W. Straßer, Interactive Cloth Simulation in

Virtual Environments, in: Proceedings of IEEE Virtual Reality 2003.

[KSW+03] Michael Keckeisen, Stanislav L. Stoev, Markus Wacker, Matthias Feurer and Wolfgang

Straßer, A User Study On Advanced Interaction Techniques in the Virtual Dressmaker

Application, in: Proceedings of HCI International 2003.

[LV94] Lazarus, A. and Verroust, A.: Feature-based shape transformation for polyhedral objects. Fifth Eurographics Workshop on Animation and Simulation, Oslo, Norway, 1994.

[Meseth03a] J. Meseth, G. Müller, M. Sattler, R. Klein, BTF Rendering for Virtual Environments,

Virtual Concepts 2003, 2003.

[Meseth03b] J. Meseth, G. Müller, R. Klein, Preserving Realism in Real-Time Rendering of

Bidirectional Texture Functions, OpenSG Symposium 2003, 2003.

[MKE03] J. Mezger, S. Kimmerle and O. Etzmuß. Hierarchical Techniques in Collision Detection for

Cloth Animation. In Journal of WSCG 2003.

[Müller03] G. Müller, J. Meseth, R. Klein, Compression and Real-Time Rendering of Measured BTFs

Using Local PCA, Vision, Modeling and Visualisation 2003, 2003.

[Sattler03] M. Sattler, R. Sarlette, R. Klein, Efficient and Realistic Visualization of Cloth,

Eurographics Symposium on Rendering 2003, 2003.

[WKK+02] Markus Wacker, Michael Keckeisen, Stefan Kimmerle and Johannes Mezger, Fortschritte

in der Textilsimulation für Fashion on Demand, in: Tagungsband 1. Paderborner Workshop

Augmented Reality Virtual Reality in der Produktentstehung, 2002.

[WKS+03] Markus Wacker, Michael Keckeisen, Stanislav L. Stoev and Wolfgang Straßer, A

Comparative Study On User Performance in the Virtual Dressmaker Application, in:

Proceedings of ACM VRST 2003.

HUMAN SOLUTIONS GmbH, Kaiserslautern Project coordination, Customer –Virtualization, Virtual Shop at the POS, Virtual E-Commerce Shop

Institute of Computer Science II, University of Bonn Efficient and realistic visualization of Cloth

WSI/GRIS, University of Tübingen Physically-Based Cloth Simulation

Fraunhofer IGD, Darmstadt Pre-Positioning of Garment, Interactive Java-based Garment Simulation

Hohenstein Institute for Clothing Physiology Physical Textile Parameters

DFKI GmbH, Kaiserslautern Interactive individual clothing catalog

Odermark, Goslar Individualized garment production

Cove & Co., Düsseldorf Pilot installation, innovative shop concepts