Volume-Surface Collision Detection

In this paper we present a novel haptic rendering method for exploration of volumetric data. It addresses a recurring flaw in almost all related approaches, where the manipulated object, when moved too quickly, can go through or inside an obstacle. Additionally, either a specific topological structure for the collision objects is needed, or extra speed-up data structures should be prepared. These issues could make it difficult to use a method in practice. Our approach was designed to be free of such drawbacks. An improved version of the method presented here does not have the issues of the original method – oscillations of the interaction point and wrong friction force in some cases. It uses the ray casting technique for collision detection and a path finding approach for rigid collision response. The method operates directly on voxel data and does not use any precalculated structures, but uses an implicit surface representation being generated on the fly. This means that a virtual scene may be both dynamic or static. Additionally, the presented approach has a nearly constant time complexity independent of data resolution.

1997

Surgical simulation has many applications in education and training, surgical planning, and intra-operative assistance. However, extending current surface-based computer graphics methods to model phenomena such as the deformation, cutting, tearing, or repairing of soft tissues pose significant challenges for real-time interactions. In this paper, the use of volumetric methods for modeling complex anatomy and tissue interactions is introduced. New techniques for modeling soft tissue deformation and tissue cutting at interactive rates are detailed. In addition, an initial prototype for simulating arthroscopic knee surgery that has resulted from an ongoing collaboration is described. Volumetric models for the knee simulator were derived from 3D Magnetic Resonance Imaging. Visual and haptic feedback is provided to the user via real-time volume and polygon rendering and a force feedback device.

Teleoperators and Virtual Environments, 1998

We propose an accurate collision detection algorithm for use in virtual reality applications. The algorithm works for three-dimensional graphical environments where multiple objects, represented as polyhedra (boundary representation), are undergoing arbitrary motion (translation and rotation). The algorithm can be used directly for both convex and concave objects and objects can be deformed (nonrigid) during motion. The algorithm works efficiently by first reducing the number of face pairs that need to be checked accurately for interference, by first localizing possible collision regions using bounding box and spatial subdivision techniques. Face pairs that remain after this pruning stage are then accurately checked for interference. The algorithm is efficient, simple to implement, and does not require any memory-intensive auxiliary data structures to be precomputed and updated. The performance of the proposed algorithm is compared directly against other existing algorithms, e.g., the separating plane algorithm, octree update method, and distance-based method. Results are given to show the efficiency of the proposed method in a general environment.

Proceedings Computer Animation 1999, 1999

We present a simple method for performing real-time collision detection in a virtual surgery environment. The method relies on the graphics hardware for testing the interpenetration between a virtual deformable organ and a rigid tool controlled by the user. The method enables to take into account the motion of the tool between two consecutive time steps. For our specific application, the new method runs about a hundred times faster than the well known orientedbounding-boxes tree method .

Mathematics and Visualization, 2016

We describe a method for combining and visualizing a set of overlapping volume images with high resolution but limited spatial extent. Our system combines the calculation of a registration metric with ray casting for direct volume rendering into a combined operation performed on the graphics processing unit (GPU). The combined calculation reduces memory traffic, increases rendering frame rate, and makes possible interactive-speed, usersupervised, semi-automatic combination of many component volume images. For volumes that do not overlap any other imaged volume, the system uses contextual information provided in the form of an overall 2D background image to calculate a registration metric.

If two closed polygonal objects with outfacing normals intersect each other there exist one or more lines that intersect these objects at at least two consecutive front or back facing object points. In this work we present a method to efficiently detect these lines using depth-peeling and simple fragment operations. Of all polygons only those having an intersection with any of these lines are potentially colliding. Polygons not intersected by the same line do not intersect each other. We describe how to find all potentially colliding polygons and the potentially colliding pairs using a mipmap hierarchy that represents line bundles at ever increasing width. To download only potentially colliding polygons to the CPU for polygon-polygon intersection testing, we have developed a general method to convert a sparse texture into a packed texture of reduced size. Our method exploits the intrinsic strength of GPUs to scan convert large sets of polygons and to shade billions of fragments at interactive rates. It neither requires a bounding volume hierarchy nor a pre-processing stage, so it can efficiently deal with very large and deforming polygonal models. The particular design makes the method suitable for applications where geometry is modified or even created on the GPU.

2012 International Conference on Cyberworlds, 2012

Haptic exploration adds an additional dimension to working with 3D data: a sense of touch. This is especially useful in areas such as medical simulation, training and pre-surgical planning, as well as in museum display, sculpting, CAD, military applications, assistive technology for blind and visually impaired, entertainment and others. There exist different surface-and voxel-based haptic rendering methods. Unaddressed practical problems for almost all of them are that no guarantees for collision detection could be given and/or that a special topological structure of objects is required. Here we present a novel and robust approach based on employing the ray casting technique to collision detection, which does not have the aforementioned drawbacks while guaranteeing nearly constant time complexity independent of data resolution. This is especially important for such delicate procedures as pre-operation planning. A collision response in the presented prototype system is rigid and operates on voxel data, and no precalculation is needed. Additionally, our collision response uses an implicit surface representation "on the fly", which can be used with dynamically changing objects.

International Journal of Technology, 2019

2006

This paper presents a method for fast-approximate collision detection between 3D models S undergoing rigid body motion known as oriented convex polyhedra R(S). By enclosing 3D models tightly, the fineness of detected collision can be enhanced. It is known that the large number of void areas which belongs to any 3D bounding volumes B(S) can affect the accuracy of collision detection system. Therefore, a way to compute R(S) using intersection of a set of halfspaces is described. The directions of these halfspaces are generated from calculating covariance matrix. To develop the tightest R(S), the quality of abutting corners by implementing Tribox Bounds method is improved. To detect collision between R(S), a straightforward approach by simply checking its interval pairs in local space system is performed. The proposed approach was implemented and a number of comparisons in terms of time and recorded collision with other B(S) were performed. From the conducted tests, R(S) performs well and might be a possible choice for detecting collision of 3D models undergoing rigid body motion.

2010

Volume rendering is a well known visualization technique for volumetric scalar data. Several publications already described the acceleration of this technique when using the graphical processing unit (GPU). This enables real-time viewpoint manipulations which, in turn, facilitates the interpretation. Stereo, where two slightly different images are generated for each eye, proved to be a valuable addition to this. Mostly because, apart from shading and motion parallax, stereo is one of the most important depth cues available in this context. We have written a fully object-oriented C++ framework that contains software for both GPU accelerated volume rendering and stereo image generation. Using this, the benefits of stereo are presented in a qualitative fashion. One example show how it helps doctors with the examination of CT scans, a second illustrates the benefits for other applications, here the analysis of volume data originating from material science simulations.