Enhancing detailed haptic relief for real-time interaction

The present document exposes a different approach for haptic rendering, defined as the simulation of force interactions to reproduce the sensation of surface relief in dense models. Current research shows open issues in timely haptic interaction involving large meshes, with several problems affecting performance and fidelity, and without a dominant technique to treat these issues properly. Relying in pure geometric collisions when rendering highly dense mesh models (hundreds of thousands of triangles) sensibly degrades haptic rates due to the sheer number of collisions that must be tracked between the mesh's faces and a haptic probe. Several bottlenecks were identified in order to enhance haptic performance: software architecture and data structures, collision detection, and accurate rendering of surface relief. To account for overall software architecture and data structures, it was derived a complete component framework for transforming standalone VR applications into full-fledged multi-threaded Collaborative Virtual Reality Environments (CVREs), after characterizing existing implementations into a feature-rich superset. Enhancements include: a scalable arbitrated peer-to-peer topology for scene sharing; multi-threaded components for graphics rendering, user interaction and network communications; a collaborative user interface model for session handling; and interchangeable user roles with multi-camera perspectives, avatar awareness and shared annotations. We validate the framework by converting the existing ALICE VR Navigator into a complete CVRE, showing good performance in collaborative manipulation of complex models. To specifically address collision detection computation, we derive a conformal algebra treatment for collisions among points, segments, areas, and volumes, based on collision detection in conformal R{4,1} (5D) space, and implemented in GPU for faster parallel queries. Results show orders of magnitude time reductions in collisions computations, allowing interactive rates. Finally, the main core of the research is the haptic rendering of surface mesostructure in large meshes. Initially, a method for surface haptic rendering was proposed, using image-based Hybrid Rugosity Mesostructures (HRMs) of per-face heightfield displacements and normalmaps layered on top of a simpler mesh, adding greater surface detail than actually present. Haptic perception is achieved modulating the haptic probe's force response using the HRM coat. A usability testbed framework was built to measure experimental performance with a common set tests, meshes and HRMs. Trial results show the goodness of the proposed technique, rendering accurate 3D surface detail at high sampling rates. This local per-face method is extended into a fast global approach for haptic rendering, building a mesostructure-based atlas of depth/normal textures (HyRMA), computed out of surface differences of the same mesh object at two different resolutions: original and simplified. For each triangle in the simplified mesh, an irregular prism is considered defined by the triangle's vertices and their normals. This prism completely covers the original mesh relief over the triangle. Depth distances and surfaces normals within each prism are warped from object volume space to orthogonal tangent space, by means of a novel and fast method for computing barycentric coordinates at the prism, and storing normals and relief in a sorted atlas. Haptic rendering is effected by colliding the probe against the atlas, and effecting a modulated force response at the haptic probe. The method is validated numerically, statistically and perceptually in user testing controlled trials, achieving accurate haptic sensation of large meshes' fine features at interactive rendering rates, with some minute loss of mesostructure detail.En aquesta tesi es presenta un novedós enfocament per a la percepció hàptica del relleu de models virtuals complexes mitjançant la simulació de les forces d'interacció entre la superfície i un element de contacte. La proposta contribueix a l'estat de l'art de la recerca en aquesta àrea incrementant l'eficiència i la fidelitat de la interacció hàptica amb grans malles de triangles. La detecció de col·lisions amb malles denses (centenars de milers de triangles) limita la velocitat de resposta hàptica degut al gran nombre d'avaluacions d'intersecció cara-dispositiu hàptic que s'han de realitzar. Es van identificar diferents alternatives per a incrementar el rendiment hàptic: arquitectures de software i estructures de dades específiques, algorismes de detecció de col·lisions i reproducció hàptica de relleu superficial. En aquesta tesi es presenten contribucions en alguns d'aquests aspectes. S'ha proposat una estructura completa de components per a transformar aplicacions de Realitat Virtual en Ambients Col·laboratius de Realitat Virtual (CRVEs) multithread en xarxa. L'arquitectura proposada inclou: una topologia escalable punt a punt per a compartir escenes; components multithread per a visualització gràfica, interacció amb usuaris i comunicació en xarxa; un model d'interfície d'usuari col·laboratiu per a la gestió de sessions; i rols intercanviables de l'usuari amb perspectives de múltiples càmeres, presència d'avatars i anotacions compartides. L'estructura s'ha validat convertint el navegador ALICE en un CVRE completament funcional, mostrant un bon rendiment en la manipulació col·laborativa de models complexes. Per a incrementar l'eficiència del càlcul de col·lisions, s'ha proposat un algorisme que treballa en un espai conforme R{4,1} (5D) que permet detectar col·lisions entre punts, segments, triangles i volums. Aquest algorisme s'ha implementat en GPU per obtenir una execució paral·lela més ràpida. Els resultats mostren reduccions en el temps de càlcul de col·lisions permetent interactivitat. Per a la percepció hàptica de malles complexes que modelen objectes rugosos, s'han proposat diferents algorismes i estructures de dades. Les denominades Mesoestructures Híbrides de Rugositat (HRM) permeten substituir els detalls geomètrics d'una cara (rugositats) per dues textures: de normals i d'alçades. La percepció hàptica s'aconsegueix modulant la força de resposta entre el dispositiu hàptic i la HRM. Els tests per avaluar experimentalment l'eficiència del càlcul de col·lisions i la percepció hàptica utilitzant HRM respecte a modelar les rugositats amb geometria, van mostrar que la tècnica proposada va ser encertada, permetent percebre detalls 3D correctes a altes tases de mostreig. El mètode es va estendre per a representar rugositats d'objectes. Es proposa substituir l'objecte per un model simplificat i un atles de mesoestructures en el que s'usen textures de normals i de relleus (HyRMA). Aquest atles s'obté a partir de la diferència en el detall de la superfície entre dos malles del mateix objecte: l'original i la simplificada. A partir d'un triangle de la malla simplificada es construeix un prisma, definit pels vèrtexs del triangle i les seves normals, que engloba el relleu de la malla original sobre el triangle. Les alçades i normals dins del prisma es transformen des de l'espai de volum a l'espai ortogonal tangent, amb mètode novedós i eficient que calcula les coordenades baricèntriques relatives al prisma, per a guardar el mapa de textures transformat en un atles ordenat. La percepció hàptica s'assoleix detectant les col·lisions entre el dispositiu hàptic i l'atles, i modulant la força de resposta d'acord al resultat de la col·lisió. El mètode s'ha validat numèricament, estadística i perceptual en tests amb usuaris, aconseguint una correcta i interactiva sensació tàctil dels objectes simulats mitjançant la mesoestructura de les mallesEn esta tesis se presenta un enfoque novedoso para la percepción háptica del relieve de modelos virtuales complejos mediante la simulación de las fuerzas de interacción entre la superficie y un elemento de contacto. La propuesta contribuye al estado del arte de investigación en este área incrementando la eficiencia y fidelidad de interacción háptica con grandes mallas de triángulos. La detección de colisiones con mallas geométricas densas (cientos de miles de triángulos) limita la velocidad de respuesta háptica debido al elevado número de evaluaciones de intersección cara-dispositivo háptico que deben realizarse. Se identificaron diferentes alternativas para incrementar el rendimiento háptico: arquitecturas de software y estructuras de datos específicas, algoritmos de detección de colisiones y reproducción háptica de relieve superficial. En esta tesis se presentan contribuciones en algunos de estos aspectos. Se ha propuesto una estructura completa de componentes para transformar aplicaciones aisladas de Realidad Virtual en Ambientes Colaborativos de Realidad Virtual (CRVEs) multithread en red. La arquitectura propuesta incluye: una topología escalable punto a punto para compartir escenas; componentes multithread para visualización gráfica, interacción con usuarios y comunicación en red; un modelo de interfaz de usuario colaborativo para la gestión de sesiones; y roles intercambiables del usuario con perspectivas de múltiples cámaras, presencia de avatares y anotaciones compartidas. La estructura se ha validado convirtiendo el navegador ALICE en un CVRE completamente funcional, mostrando un buen rendimiento en la manipulación colaborativa de modelos complejos. Para incrementar la eficiencia del cálculo de colisiones, se ha propuesto un algoritmo que trabaja en un espacio conforme R4,1 (5D) que permite detectar colisiones entre puntos, segmentos, triángulos y volúmenes. Este algoritmo se ha implementado en GPU a efectos de obtener una ejecución paralelamás rápida. Los resultadosmuestran reducciones en el tiempo de cálculo de colisiones permitiendo respuesta interactiva. Para la percepción háptica de mallas complejas que modelan objetos rugosos, se han propuesto diferentes algoritmos y estructuras de datos. Las denominadasMesoestructuras Híbridas de Rugosidad (HRM) permiten substituir los detalles geométricos de una cara (rugosidades) por una textura de normales y otra de alturas. La percepción háptica se consigue modulando la fuerza de respuesta entre el dispositivo háptico y la HRM. Los tests realizados para evaluar experimentalmente la eficiencia del cálculo de colisiones y la percepción háptica utilizando HRM respecto a modelar las rugosidades con geometría, mostraron que la técnica propuesta fue acertada, permitiendo percibir detalles 3D correctos a altas tasas de muestreo. Este método anterior es extendido a un procedimiento global para representar rugosidades de objetos. Para hacerlo se propone sustituir el objeto por un modelo simplificado y un atlas de mesostructuras usando texturas de normales y relieves (HyRMA). Este atlas se obtiene de la diferencia en detalle de superficie entre dos mallas del mismo objeto: la original y la simplificada. A partir de un triángulo de la malla simplificada se construye un prisma definido por los vértices del triángulo a lo largo de sus normales, que engloba completamente el relieve de la malla original sobre este triángulo. Las alturas y normales dentro de cada prisma se transforman del espacio de volumen al espacio ortoganal tangente, usando un método novedoso y eficiente que calcula las coordenadas baricéntricas relativas a cada prisma para guardar el mapa de texturas transformado en un atlas ordenado. La percepción háptica se consigue detectando directamente las colisiones entre el dispositivo háptico y el atlas, y modulando la fuerza de respuesta de acuerdo al resultado de la colisión. El procedmiento se ha validado numérica, estadística y perceptualmente en ensayos con usuarios, consiguiendo a tasas interactivas la correcta sensación táctil de los objetos simulados mediante la mesoestructura de las mallas, con alguna pérdida muy puntual de detall

Trabajo y Educación en la Seguridad Societal

La interrelación entre trabajo, educación y seguridad societal es un objeto de estudio e investigación con novedad original, que es investigado bajo el enfoque heurístico del modelo emergente de cuádruple hélice para la innovación en el dominio del ciberespacio; teniendo como actores a la sociedad civil, a los pueblos con su poder creador, a las instituciones de educación universitaria, a los gobiernos o administraciones de los Estados-nación, y a  los sectores de la economía real y de la economía especulativa  globalizante. Este artículo es un reporte preliminar de investigación, que presenta el estado del arte del trabajo y la educación como procesos categoriales que, objetiva o subjetivamente, impactan a la seguridad societal, y tienen efectos en la seguridad de los Estados-nación y  la Paz internacional

Hybrid Rugosity Mesostructures (HRMs) for fast and accurate rendering of fine haptic detail

The haptic rendering of surface mesostructure (fine relief features) in dense triangle meshes requires special structures, equipment, and high sampling rates for detailed perception of rugged models. Low cost approaches render haptic texture at the expense of fidelity of perception. We propose a faster method for surface haptic rendering using image-based Hybrid Rugosity Mesostructures (HRMs), paired maps with per-face heightfield displacements and normal maps, which are layered on top of a much decimated mesh, effectively adding greater surface detail than actually present in the geometry. The haptic probe’s force response algorithm is modulated using the blended HRM coat to render dense surface features at much lower costs. The proposed method solves typical problems at edge crossings, concave foldings and texture transitions. To prove the wellness of the approach, a usability testbed framework was built to measure and compare experimental results of haptic rendering approaches in a common set of specially devised meshes, HRMs, and performance tests. Trial results of user testing evaluations show the goodness of the proposed HRM technique, rendering accurate 3D surface detail at high sampling rates, deriving useful modeling and perception thresholds for this technique.Peer ReviewedPostprint (published version

Enhancing collaboration in virtual reality applications

We derive a complete component framework for transforming standalone virtual reality (VR) applications into fullfledged multithreaded collaborative virtual reality environments (CVREs), after characterizing existing implementations into a feature-rich superset. Our main contribution is placing over the existing VR tool a very concise and extensible class framework as an add-on component that provides emerging collaboration features. The enhancements include: a scalable arbitrated peer-to-peer topology for scene sharing; multi-threaded components for graphics rendering, user interaction and network communications; a streaming message protocol for client communications; a collaborative user interface model for session handling; and interchangeable user roles with multicamera perspectives, avatar awareness and shared 3D annotations. We validate the framework by converting the existing ALICE VR Navigator into complete CVRE, with experimental results showing good performance in the collaborative inspection and manipulation of complex models.Peer ReviewedPostprint (published version

Hybrid Rugosity Mesostructures (HRMs) for fast and accurate rendering of fine haptic detail

Thehapticrenderingofsurfacemesostructure(finerelieffeatures)indensetrianglemeshesrequires special structures, equipment, and high sampling rates for detailed perception of rugged models. Low cost approaches render haptic texture at the expense of fidelity of perception. We propose a faster method for sur- face haptic rendering using image-based Hybrid Rugosity Mesostructures (HRMs), paired maps with per-face heightfield displacements and normal maps, which are layered on top of a much decimated mesh, effectively adding greater surface detail than actually present in the geometry. The haptic probe’s force response algorithm is modulated using the blended HRM coat to render dense surface features at much lower costs. The proposed method solves typical problems at edge crossings, concave foldings and texture transitions. To prove the well- ness of the approach, a usability testbed framework was built to measure and compare experimental results of haptic rendering approaches in a common set of specially devised meshes, HRMs, and performance tests. Trial results of user testing evaluations show the goodness of the proposed HRM technique, rendering accurate 3D surface detail at high sampling rates, deriving useful modeling and perception thresholds for this technique

Enhancing collaboration in virtual reality applications

We derive a complete component framework for transforming standalone virtual reality (VR) applications into fullfledged multithreaded collaborative virtual reality environments (CVREs), after characterizing existing implementations into a feature-rich superset. Our main contribution is placing over the existing VR tool a very concise and extensible class framework as an add-on component that provides emerging collaboration features. The enhancements include: a scalable arbitrated peer-to-peer topology for scene sharing; multi-threaded components for graphics rendering, user interaction and network communications; a streaming message protocol for client communications; a collaborative user interface model for session handling; and interchangeable user roles with multicamera perspectives, avatar awareness and shared 3D annotations. We validate the framework by converting the existing ALICE VR Navigator into complete CVRE, with experimental results showing good performance in the collaborative inspection and manipulation of complex models.Peer Reviewe

Rendering detailed haptic textures

Rendering haptic textures seamlessly out of triangle meshes just by using geometry requires heavy work and does not allow high sampling rates for detailed, rugged models. Better approaches simulate surface texture without increasing much the complexity or processing cost, at the expense of fidelity of perception. We propose a method for rendering local height field maps out of an underlying triangle mesh, which relies in a space subdivision representation based on octrees for collision detection, and rendering individual surface detail by modulating force response using local height fields. We compare our method against a force mapping implementation for rendering/perceiving the same models with textures using normal maps. The proposed technique allows for real time perception of 3D surface detail, allowing the user to perceive the best haptic rendering alternative for a given model. Some experimental results are presented to show the goodness of the approach. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Haptic Rendering 1

Hybrid Rugosity Mesostructures (HRMs) for fast and accurate rendering of fine haptic detail

The haptic rendering of surface mesostructure (fine relief features) in dense triangle meshes requires special structures, equipment, and high sampling rates for detailed perception of rugged models. Low cost approaches render haptic texture at the expense of fidelity of perception. We propose a faster method for surface haptic rendering using image-based Hybrid Rugosity Mesostructures (HRMs), paired maps with per-face heightfield displacements and normal maps, which are layered on top of a much decimated mesh, effectively adding greater surface detail than actually present in the geometry. The haptic probe’s force response algorithm is modulated using the blended HRM coat to render dense surface features at much lower costs. The proposed method solves typical problems at edge crossings, concave foldings and texture transitions. To prove the wellness of the approach, a usability testbed framework was built to measure and compare experimental results of haptic rendering approaches in a common set of specially devised meshes, HRMs, and performance tests. Trial results of user testing evaluations show the goodness of the proposed HRM technique, rendering accurate 3D surface detail at high sampling rates, deriving useful modeling and perception thresholds for this technique.Peer Reviewe

A hybrid rugosity mesostructure (HRM) for faster rendering of fine haptic detail

We propose a faster method for surface haptic rendering using image-based Hybrid Rugosity Mesostructures (HRMs), paired maps with per-face height eld displacements and normalmaps, which are layered on top of a much decimated mesh. The haptic probe's force response algorithm is modulated using the blended HRM coat to render surface features at much lower costs. The proposed method solves typical problems at edge crossings, concave foldings and texture transitions. To prove the wellness of the approach, a usability testbed framework was built to measure and compare experimental results of haptic rendering approaches. Trial results of user testing evaluations show the goodness of the proposed HRM technique, rendering accurate 3D surface detail at high sampling rates, deriving useful modeling and perception thresholds for this technique.Postprint (published version

A hybrid rugosity mesostructure (HRM) for faster rendering of fine haptic detail

We propose a faster method for surface haptic rendering using image-based Hybrid Rugosity Mesostructures (HRMs), paired maps with per-face height eld displacements and normalmaps, which are layered on top of a much decimated mesh. The haptic probe's force response algorithm is modulated using the blended HRM coat to render surface features at much lower costs. The proposed method solves typical problems at edge crossings, concave foldings and texture transitions. To prove the wellness of the approach, a usability testbed framework was built to measure and compare experimental results of haptic rendering approaches. Trial results of user testing evaluations show the goodness of the proposed HRM technique, rendering accurate 3D surface detail at high sampling rates, deriving useful modeling and perception thresholds for this technique