25,602 research outputs found
Entwicklung und Evaluation einer auf der Hauptkomponentenanalyse basierenden Bounding Volume Hierarchy
Die vorliegende Arbeit beschäftigt sich im übergeordneten Kontext mit den Bounding Volume Hierarchies zur Veinfachung des Intersection Testings beim Raytracing. Die derzeitige Problematik besteht vor allem in der immer noch zu optimierenden Laufzeit. Dementsprechend wird trotz der bereits bestehenden Beschleunigungsdatenstrukturen wie unter anderem der Bounding Volume Hierarchy versucht, effizientere Strukturen oder Erstellungsprozeduren zu entwickeln. Für die Bounding Volume Hierarchy bedeutet dies, dass vor allem hinsichtlich verschiedener Splitting-Methoden und Möglichkeiten für die Baumoptimierung geforscht wird. Explizit wird daher innerhalb dieser Arbeit untersucht, wie die Bounding Volume Hierarchy durch die Verwendung der Hauptkomponentenanalyse bei der Erstellung optimiert werden kann und wie effizient der daraus resultierende Ansatz gegenüber der klassischen Bounding Volume Hierarchy sowie deren Splitting-Methoden ist. Eine Evaluation anhand 12 verschiedener Szenen zeigte, dass der vorliegende Ansatz unter Verwendung der SAH-Methode wie auch mit der Middle-Methode 17.70% respektive 13.14% geringere Renderlaufzeiten als der distanzbasierte Ansatz aufweist. Des Weiteren konnte mittels der kombinierten Verwendung aus klassischer SAH-Methode und PCA-basierter SAH-Methode eine weitere Verbesserung um 6.65% gegenüber der SAH-Methode der PCA-BVH erreicht werden
Konstruksi Bounding Volume Hierarchy dengan Metode Agglomerative Clustering untuk Meningkatkan Performa Ray Tracing
Ray Tracing sebagai algoritma rendering yang menghasilkan citra realistis memiliki beberapa kekurangan. Salah satu di antaranya adalah perhitungan persilangan ray-object pada tiap pixel yang memakan 75% waktu dari keseluruhan proses rendering. Penelitian ini menerapkan metode yang diharapkan dapat mempersingkat proses perhitungan persilangan ray-object dengan membangun struktur data berupa binary tree. Tree yang dibangun sering juga disebut sebagai Bounding Volume Hierarchy (BVH) di mana masing-masing node-nya adalah sebuah container. Struktur data tersebut akan dibangun dengan metode Approximate Agglomerative Clustering (AAC) yang merupakan metode bottom-up clustering dengan top-down preprocessing. Metode AAC dengan parameter yang baik dapat meningkatkan performa Ray Tracing. Metode-metode yang diterapkan sangat mudah diparalelkan sehingga performa algoritma meningkat jika dijalankan pada lingkungan paralel. Hasil uji coba menunjukkan peningkatan kecepatan hingga 3 kali lipat dibandingkan tanpa menerapkan paralelisme. Pada hasil uji coba, juga didapatkan dua jenis parameter yang masing-masing memiliki karakteristik tersendiri (6= cepat, 12= kualitas baik)
New Geometric Data Structures for Collision Detection
We present new geometric data structures for collision detection and more, including: Inner Sphere Trees - the first data structure to compute the peneration volume efficiently. Protosphere - an new algorithm to compute space filling sphere packings for arbitrary objects. Kinetic AABBs - a bounding volume hierarchy that is optimal in the number of updates when the objects deform. Kinetic Separation-List - an algorithm that is able to perform continuous collision detection for complex deformable objects in real-time. Moreover, we present applications of these new approaches to hand animation, real-time collision avoidance in dynamic environments for robots and haptic rendering, including a user study that exploits the influence of the degrees of freedom in complex haptic interactions. Last but not least, we present a new benchmarking suite for both, peformance and quality benchmarks, and a theoretic analysis of the running-time of bounding volume-based collision detection algorithms
Improved Collision Detection and Response Techniques for Cloth Animation
In the animation of deformable objects, collision detection and
response are crucial for the performance. Contrary to volumetric
bodies, the accuracy requirements for the collision treatment
of textiles are particularly strict because any overlapping is
visible. Therefore, we apply methods specifically designed for
deformable surfaces that speed up the collision detection.
In this paper the efficiency of bounding volume hierarchies is improved
by adapted techniques for building and traversing these hierarchies.
An extended set of heuristics is
described that allows to prune the hierarchy. Oriented inflation
of bounding volumes enables us to detect proximities with a minimum
of extra cost. Eventually, the distance of the mesh faces is computed
accurately, and constraints respond to the collisions
Revisión de literatura de jerarquía volúmenes acotantes enfocados en detección de colisiones
(Eng) A bounding volume is a common method to simplify object representation by using the composition of geometrical shapes that enclose the object; it encapsulates complex objects by means of simple volumes and it is widely useful in collision detection applications and ray tracing for rendering algorithms. They are popular in computer graphics and computational geometry. Most popular bounding volumes are spheres, Oriented-Bounding Boxe s (OBB’ s), Axis-Align ed Bound ing Boxes (AABB’ s); moreover , the literature review includes ellipsoids, cylinders, sphere packing, sphere shells , k-DOP’ s, convex hulls, cloud of points, and minimal bounding boxe s, among others. A Bounding Volume Hierarchy is ussualy a tree in which the complete object is represented thigter fitting every level of the hierarchy. Additionally, each bounding volume has a cost associated to construction, update, and interference te ts. For instance, spheres are invariant to rotation and translations, then they do not require being updated ; their constructions and interference tests are more straightforward then OBB’ s; however, their tightness is lower than other bounding volumes. Finally , three comparisons between two polyhedra; seven different algorithms were used, of which five are public libraries for collision detection.(Spa) Un volumen acotante es un método común para simplificar la representación de los objetos por medio de composición
de formas geométricas que encierran el objeto; estos encapsulan objetos complejos por medio de volúmenes simples y
son ampliamente usados en aplicaciones de detección de colisiones y trazador de rayos para algoritmos de renderización.
Los volúmenes acotantes son populares en computación gráfica y en geometría computacional; los más populares son las
esferas, las cajas acotantes orientadas (OBB’s) y las cajas acotantes alineadas a los ejes (AABB’s); no obstante, la literatura
incluye elipses, cilindros empaquetamiento de esferas, conchas de esferas, k-DOP’s, convex hulls, nubes de puntos y cajas
acotantes mínimas, entre otras. Una jerarquía de volúmenes acotantes es usualmente un árbol, en el cual la representación
de los objetos es más ajustada en cada uno de los niveles de la jerarquía. Adicionalmente, cada volumen acotante tiene
asociado costos de construcción, actualización, pruebas de interferencia. Por ejemplo, las esferas so invariantes a rotación
y translación, por lo tanto no requieren ser actualizadas en comparación con los AABB no son invariantes a la rotación.
Por otro lado la construcción y las pruebas de solapamiento de las esferas son más simples que los OBB’s; sin embargo, el
ajuste de las esferas es menor que otros volúmenes acotantes. Finalmente, se comparan dos poliedros con siete algoritmos
diferentes de los cuales cinco son librerías públicas para detección de colisiones
Surface-Surface-Intersection Computation using a Bounding Volume Hierarchy with Osculating Toroidal Patches in the Leaf Nodes
We present an efficient and robust algorithm for computing the intersection curve of two freeform surfaces using a Bounding Volume
Hierarchy (BVH), where the leaf nodes contain osculating toroidal patches. The covering of each surface by a union of tightly fitting
toroidal patches greatly simplifies the geometric operations involved in the surface-surface-intersection computation, i.e., the bounding
of surface normals, the detection of surface binormals, the point projection from one surface to the other surface, and the intersection
of local surface patches. Moreover, the hierarchy of simple bounding volumes (such as rectangle-swept spheres) accelerates the
geometric search for the potential pairs of surface patches that may generate some curve segments in the surface-surface-intersection.
We demonstrate the effectiveness of our approach by using test examples of intersecting two freeform surfaces, including some highly
non-trivial examples with tangential intersections. In particular, we test the intersection of two almost identical surfaces, where one
surface is obtained from the same surface, using a rotation around a normal line by a smaller and smaller angle θ = 10−k degree,
k = 0, · · · , 5. The intersection results are often given as surface subpatches in some highly tangential areas, and even as the whole
surface itself, when θ = 0.00001◦
Efficient Ray Tracing of CSG Models
Tato práce zkoumá metody sledování paprsku v kombinaci s konstruktivní geometrií těles (CSG). Dále navrhuje způsob využití Embree, vysoce optimalizované knihovny používající hierarchii obálek pro sledování paprsků v trojúhelníkových sitích, pro zobrazení CSG v kombinaci s trojúhelníkovými sítěmi.This work explores ray tracing of constructive solid geometry (CSG) and its acceleration in combination with ray tracing triangles. It proposes a way how to exploit Embree, a highly optimized library using bounding volume hierarchy for ray tracing triangle meshes, for rendering CSG with triangle meshes
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