Hierarchical Bounding Box Research Articles

Dynamic obstacle avoidance and trajectory planning of five-axis redundant industrial manipulator

Aiming at the problem that five axis redundant industrial manipulator dynamic obstacle avoidance and trajectory planning algorithm does not consider the minimum difference of each joint of the manipulator, which leads to low success rate of obstacle avoidance planning, slow convergence speed of path cost and long time of obstacle avoidance planning, a simulation study on dynamic obstacle avoidance trajectory planning of five axis redundant industrial manipulator is proposed. According to the D-H rule, the coordinate system of each link joint of the five axis redundant industrial manipulator is established, and the forward and inverse kinematics of the five axis redundant industrial manipulator is analyzed. AABB's hierarchical bounding box tree algorithm is used to detect the collision of five axis redundant industrial manipulator. This paper uses harmony search algorithm to plan the obstacle avoidance path of five axis redundant industrial manipulator, determines the objective function and constraints of the optimization problem, sets algorithm parameters, initializes harmony memory, creates new harmony, updates harmony memory, checks and searches the target state, achieves the maximum number of iterations, and realizes the dynamic obstacle avoidance and trajectory planning of five axis redundant industrial manipulator. The experimental results show that the path cost of the proposed algorithm converges faster, and can effectively improve the success rate of obstacle avoidance planning and shorten the time of obstacle avoidance planning.

Large-scale Aerosols Visualization Based on the Accelerated Ray Casting Algorithm

The ray casting algorithm is a widely used basic volume rendering algorithm, but traditional ray casting algorithms have some disadvantages such as low efficiency, slow speed and large resource consumption when rendering aerosol data such as smoke, fog and dust in 3D scenes. In this regard, this paper proposes a large-scale aerosol visualization method based on a ray-casting acceleration algorithm. A large part of the computational work in a traditional ray casting algorithm is to compute a large volume of data from the underlying scalar field. Therefore, the accelerated design of the ray casting algorithm should first consider avoiding sampling of empty spaces and invalid voxels, and culling areas in the volume data that do not contribute to volume rendering. The method in this paper firstly optimizes and accelerates the traditional ray casting algorithm through the hierarchical bounding box tree, and combines the illumination model to enhance the color rendering of each voxel. Unnecessary space debris reduces hardware load, improves rendering speed, and meets the real-time rendering requirements of large-scale aerosols.

Research on hybrid bounding box interference check algorithm for robot offline simulation system

Aiming at the problem that the traditional industrial robot may interfere with the workpiece when running in the offline simulation environment, a hybrid bounding box algorithm based on octree is proposed. First, AABB is used for rough interference checks, which quickly eliminates the pairs of impossible objects to intersect, then OBB hierarchical bounding box is used for precise interference checks. A new OBB construction method is proposed, which recalculates the semi-axis length and centre of the constructed traditional OBB to make it surround the object as much as possible and reduce the space gap. A traversal method based on distance priority is proposed, which traversed the closest node every time by maintaining a priority queue. And in the update strategy, “update on demand” is adopted, which discards updating the entire tree before each intersection and only updates the current node during the intersection traversal to achieve the purpose of partial update. Experiments show that the proposed hybrid bounding box algorithm can detect interference faster and perform better real-time performance and accuracy.

Study on Collision Detection and Force Feedback Algorithm in Virtual Surgery.

The development of virtual reality technology is expected to solve traditional surgical training. The lack of methods has brought revolutionary advances in technology. The virtual surgery system based on collision detection and force feedback can enable the operator to have stronger interaction, which is an exploration of the feature of touch in virtual reality technology. Reality is an important indicator of the virtual surgical system. This article improves the realism of the system from the visual and tactile senses and uses the surrounding ball collision detection and force feedback algorithms to build a realistic surgical platform. In the virtual surgery training system, the introduction of force feedback greatly improves the sense of presence during virtual surgery interaction. The operator can feel the softness and hardness of different tissues and organs through the force feedback device. Virtual reality is an interdisciplinary comprehensive technology that has been widely used in military, film, medical, and gaming fields. Virtual reality can simulate the objective world and display it visually, making people feel immersive. Virtual surgery provides surgeons with a recyclable surgical practice platform and can help doctors perform preoperative rehearsals and predict the results of surgery. The design of collision detection and force feedback algorithms is a prerequisite to ensure the immersion and transparency of the virtual surgical training system. This article mainly introduces the collision detection and force feedback algorithm research in virtual surgery, with the intention of providing some ideas and directions for the development of virtual surgery. This paper proposes two collision detection algorithms, space decomposition method and hierarchical bounding box method, and three force feedback algorithms including spring mass point algorithm, Runge–Kutta method, and Euler method to construct virtual surgery collision detection and force feedback. Experiment with the Overall System Architecture. This paper proves through experimental results that the average collision detection time after the application of the improved collision detection and force feedback algorithm in the virtual surgery system is more than 80.7% less than the traditional method, which greatly improves the detection speed.

Combination Constraints of Multiple Fields for Implicit Modeling of Ore Bodies

In this paper, we introduce combination constraints for modeling ore bodies based on multiple implicit fields interpolation. The basic idea of the method is to define a multi-labeled implicit function that combines different sub-implicit fields by the combination operations, including intersection, union and difference operators. The contribution of this paper resides in the application of combination of more general implicit fields with combination rules for the implicit modeling of ore bodies, such that the geologist can construct constraints honoring geological relationships more flexibly. To improve the efficiency of implicit surface reconstruction, a pruning strategy is used to avoid unnecessary calculations based on the hierarchical bounding box of the operation tree. Different RBF-based methods are utilized to study the implicit modeling cases of ore bodies. The experimental results of several datasets show that the combination constraints are useful to reconstruct implicit surfaces for ore bodies with mineralization rules involving multiple fields.

An improved optimal algorithm for collision detection of hybrid hierarchical bounding box

Collision detection is currently a hot issue in virtual reality and other fields. The efficiency and accuracy of collision detection directly affect the real-time update effect of the virtual reality environment, and it is also an important indicator that affects the user's interactive experience. In a complex virtual reality scene, if the traditional collision detection algorithm (Sphere-OBB) is adopted and the tree structure traversal is used to realize the bounding box traversal detection, the accuracy remains unchanged, but the detection complexity is reduced. If the RAPID collision detection algorithm is used, the separated axis test method and the two-layer hybrid hierarchical surrounding tree structure are used, although the amount of calculation is large, the detection efficiency is improved. Using the separation axis (SAT) algorithm and using the separation axis theorem to determine the vector axis can save a lot of calculation time. The purpose of this research is to propose an improved hybrid-level bounding box collision detection optimization algorithm (ASO) based on the traditional hybrid-level bounding box collision detection algorithm. Firstly, based on the spatio-temporal correlation theory, the hybrid hierarchical bounding box hierarchical tree structure is improved to AABB and OBB from top to bottom. The synchronous descent rule is used to realize the traversal of nodes, and then the triangle area weighting method is used to improve the calculation method of the bottom OBB bounding box node center, solve the bounding box vertex covariance matrix, and improve the efficiency and accuracy of collision detection. The experimental results show that the algorithm proposed in this paper is 35.6% faster than the RAPID detection speed and 29.9% faster than the separation axis (SAT) detection speed under the same accuracy. In the multi-object collision detection, compared with the latest research, the algorithm in this paper shortens the intersection detection time, improves the collision detection efficiency, and meets the real-time update requirements of complex virtual reality scenes.

Application of improved algorithm based on sphere OBB hybrid hierarchical bounding box in Teaching

In this paper, on the premise of analyzing the theoretical knowledge of collision detection algorithm, the advantages and disadvantages of several commonly used hierarchical bounding box methods are compared and analyzed, and then the traditional collision detection algorithm is studied. This paper presents a new collision detection algorithm. After preprocessing, the first order collision detection based on the separation axis theorem is used to exclude a large number of disjoint spatial model objects through preprocessing. The purpose of adding primary collision detection is to further investigate disjoint object pairs, and prepare for the final detailed detection stage. The pre-determined OBB bounding box is used for fast collision detection, and its storage structure and mode are optimized quickly. After preprocessing, it effectively eliminates the obviously disjoint space object pairs, reduces a large number of operations, and improves the detection efficiency.

A parallel construction method based on linear hierarchical bounding box without stack

The intersect operation of geometry is a common method of collision detection. To achieve a fast intersect operation, a hierarchical bounding box must be quickly constructed. This paper proposes an effective space division method for constructing high-quality linear hierarchical bounding boxes through ray tracing. This method can generate more regular axial bounding boxes into a complete binary tree. This structure can be completely parallel on the GPU, and effective parallelization can ensure the fastest tree-building time. The algorithm in this paper uses a non-stack ray tracing method to increase the frame rate of the 3D model rendering in the graphics processing unit and reduce the construction time of the bounding box. The experimental analysis of construction time, frame rate, average number of intersections and other performance indicators, the experimental results show that the use of stack-free midpoint splitting method and surface heuristic splitting method to ensure rapid construction time and efficient ray traversal performance, improve the object’s light traversal efficiency.

Research on parallel algorithm based on AABB bounding box coordinate chain method

With the rapid development of virtual reality technology and collision detection technology, virtual reality has become a lot of research fields in China. Collision detection is one of the most important technologies, and virtual surgery simulation has gradually become an important application of medicine in virtual reality technology. Virtual surgery can not only provide a skilled training platform for medical staff, but also analyze the feasibility and danger of surgical scheme, so that medical staff can have the same authenticity and strong immersion in virtual environment as in physical surgery. In this paper, a mixed hierarchical bounding box is constructed to detect the collision between the virtual human soft tissue and the rigid tissue of surgical instruments, and a parallel algorithm, fast bounding box coordinate chain calculation, compression storage and so on are introduced. For the deformation model of the software which is difficult to construct, the collision detection can be completed quickly and accurately, which can effectively save the collision detection time and improve the real-time performance of the collision.

A Natural Interaction Method of Multi-Sensory Channels for Virtual Assembly System of Power Transformer Control Cabinet

The more sensory channels are equipped in a virtual assembly system, the more real users feel in the whole system, however, most of the existing virtual assembly systems are based on the natural interaction method of one or two sensory channels. Thus, this paper proposes a novel virtual assembly system integrating multi-sensory channels, including gesture interaction, Chinese speech interaction, tactile interaction, 3D display and real-time display of real environment pictures in the virtual environment. To improve the operability of the virtual environment, we analyze the parallel virtual assembly sequence on the basis of two-hand interaction, and the assembly priority is prompted based on UI interface. For ease of operation, we present a method of viewpoint control based on gesture interaction and the coordinate threshold of spatial position. A hierarchical bounding box collision detection algorithm based on volume difference is proposed to improve the efficiency of collision feedback and collision avoidance. In addition, the power equipment models are exhibited in the virtual scene, as the exhibits of the virtual roaming process. Finally, to evaluate the training effect of this system, a comparative experiment is designed to compare the participants’ experience and the effect of assembly training. The experimental results show that the virtual assembly system of natural interaction with multi-sensory channels is flexible and immersive.

Research on 3D Simulation of Fabricated Building Structure Based on BIM

In order to solve the problem of low accuracy and poor analysis of traditional fabricated building structure, the new BIM-based 3D simulation method for fabricated building structure is proposed. Drawings and related documents are obtained from the database. Through the REVIT software, the 3D simulation model is drawn by the BIM technical team and the fabricated building structure is simulated in 3D. The design of the REVIT platform is realized by three stages: structural space constraint relationship determination, geometric component generation and color processing. The spatial mesh structure is used to describe the geometric components, and the homomorphic filtering is used to process the colors. The bounding box and the hierarchical bounding box method are used to detect the collision of the steel structure. For static combinations, the bounding box method is used to implement collision detection, and the hierarchical bounding box method is used to detect dynamic combinations. The experimental results show that the proposed method can effectively realize the 3D simulation of the fabricated building structure, and the detection results are accurate, the overall performance is excellent, and the user satisfaction is high.

Research on Collision Detection in Virtual Measurement Scene

Facing the need of virtual laboratory of engineering drawing, virtual measurement module is developed. According to the collision features, the collision detection algorithm based on OBB hierarchical bounding box method is applied to the virtual measurement scene. A scanning sampling method is used to simulate the dynamic measurement process. As to the sampling point, the means of dividing the value by two points and limiting the step distance is obtained. The method of determining the traversal order by the distance of the center of the bounding box is proposed in the process of traversing the tree to reduce the average lookup depth of the bounding box tree intersection test. Accurate collision detection between STL model [1] and virtual measurement tool using VS2013 and OpenGL. Through experimental verification, the whole process satisfies the accuracy and real-time requirement of the measurement, and proves the validity and fastness of the collision detection algorithm and its optimization method.

Research on Bounding Volume Boxes Collision Detection Algorithm in Virtual Reality Technology

Abstract This paper take the development of virtual campus roaming system as an example. Aiming at the defects of the different kinds of bounding boxes collision detection technology, analyzes the advantages of the hybrid hierarchical bounding box collision detection algorithm based on spheres and oriented bounding box, and described the way to construct it. Finally, the algorithm is tested in the VC and Unity3d engine, a good result is obtained.

Collision detection for virtual environment using particle swarm optimization with adaptive cauchy mutation

Rapid and accurate detection of collision between virtual objects is crucial for many virtual reality based applications. In order to ensure a high-level of accuracy and to meet the real-time requirement, a fast collision detection algorithm between soft bodies is proposed. The developed algorithm is a combination of stochastic methods and particle swarm optimization with adaptive Cauchy mutation. The hierarchical bounding box method is used for a rough detection in order to filter out obvious disjoint space, and the problem is converted to a nonlinear optimization problem based on the distance of points. Then particle swarm optimization with adaptive Cauchy mutation is used to find the optimal solution. When it is updated iteratively, keeping some particles experience value and variation of other particles avoids particles trapped in local optimum, which further accelerates the speed of collision detection. The algorithm is implemented and evaluated through experiments and the results confirm the advantages of the developed algorithm.

Deformation similarity clustering based collision detection in clothing simulation

Purpose – The 3D dynamic clothing simulation is widely used in computer-added garment design. Collision detection and response are the essential component and also the efficiency bottleneck in the simulation. The purpose of this paper is to propose a high efficient collision detection algorithm for 3D clothing-human dynamic simulation to achieve both real-time and virtually real simulation effects. Design/methodology/approach – The authors approach utilizes the offline data learning results to simplify the online collision detection complexity. The approach includes two stages. In the off-line stage, model triangles with most similar deformations are first, partitioned into several near-rigid-clusters. Clusters from the clothing model and the human model are matched as pairs according to the fact that they hold the potential to intersect. For each cluster, a hierarchical bounding box tree is then constructed. In the on-line stage, collision detection is checked and treated parallelly inside each cluster pairs. A multiple task allocation strategy is proposed in parallel computation to ensure efficiency. Findings – Reasonably partitioning the 3D clothing and human model surfaces into several clusters and implementing collision detection on these cluster pairs can efficiently reduce the model primitive amounts that need be detected, consequently both improving the detection efficiency and remaining the simulation virtual effect. Originality/value – The current methods only utilize the dynamic clothing-human status; the authors algorithm furthermore combines the intrinsic correspondence relationship between clothing and human clusters to efficiently shrink the detection query scope to accelerate the detection speed. Moreover, partitioning the model into several independent clusters as detection units is much more profitable for parallel computation than current methods those treat the model entirety as the unit.

Adaptive Multilevel Meshes for Cloth Simulation

A novel method based on multilevel meshes is proposed to simulate the cloth draping process rapidly on a complex model. Considering of the difficulty of computing the realtime collision between cloth and complex models by normally methods, the draping process of cloth is divided into several phases and at each phase the mesh size is smaller than its previous one. The optimized 1-to-4 split is used to drive the rapid changes in the grid hierarchy and to simplify the calculations. We choose the widely used ellipsoid as the bounding cell to enclose the complex models in the environment. The ellipsoid avoids the complex structure of hierarchical bounding box and eliminates the impossible collision model area rapidly. Experiments demonstrate that this method can accelerate the draping process of cloth and decrease the number of iterations and the calculation of collision detection. Further mesh refinement improves the reality of cloth when it reaches the final position and ensures the realism of the simulation in real time.

Research on Collision Detection Algorithm Based on OBB

To enhance the real-time and accuracy of collision detection in virtual environment, introduces oriented bounding box (OBB) technology of hierarchical bounding box collision detection algorithm:construction of bounding box, generation of bounding box tree, implementation of collision detection algorithm,overlap judgement of bounding box. Collision detection algorithm based on OBB in this article is applied to solve the problem of collision detection between rigid bodies.

MO-D-BRB-06: JUNIOR INVESTIGATOR WINNER - Fast and Accurate Patient Specific Collision Detection for Radiation Therapy.

To develop a fast and generalizable method which can identify all possible hardware collisions specific to a given patient setup before treatment planning. An anthropomorphic phantom placed in a typical breast setup using a wingboard was simulated on a CT scanner and the phantom body contour, table, and gantry geometry were made into polygon meshes using 3D modeling software. In the treatment room, a limited physical search of the collision positive zones was performed using the positioned phantom. A software tool that incorporated a generalized hierarchical bounding box (HBB) collision detection algorithm was developed and used to virtually map out the entire collision space by transforming the positions of the polygonal geometry over a given parameter range. The geometry containing 47K polygons was mapped over a space of 6480 states with an average transform/collision check of 5.5ms, for a total time of 35.6s on a 3.14GHz dual core computer with 4GB memory. The computed collision space, using receiver operating curve analysis had an accuracy of 96.35%, and a positive predictive value of 91.2%. This work demonstrates a framework that can provide a fast and accurate map of the collision free space specific to any patient setup. Differences in physical and simulated collision space is attributed to inaccuracies of the geometrical models used. Future work includes improving the efficiency of the algorithm, enhancing the geometrical models and increasing the dimensions of the search.

An Improved Bounding Box Algorithm to Collision Detection for Virtual Environment

The paper proposed a parallel collision detection algorithm based on bounding box-tree. The hierarchical bounding box –tree was built by dividing the polyhedron into tetrahedron. The collision detection can be completed by the method searching the bounding box-tree from top to bottom or from bottom to top. The first top-down search algorithm can give accurate calculation of collision detection, the second bottom-up search algorithms is suitable to the object which collides. The algorithm quickly eliminated the possibility of collision between objects far apart. The application of parallel method improves the collision speed for further step. And it well adapted to the needs of the dynamic collision detection. Test results showed that the algorithm greatly improved the collision detection’s speed in virtual environment.

Research on Bounding Box-Tree Algorithm for Collision Detection

In order to improve the efficiency of the collision detection for polyhedron, the paper proposed a collision detection algorithm based on bounding box-tree. The hierarchical bounding box –tree was built by dividing the polyhedron into tetrahedron. The collision detection can be completed by the method searching the bounding box-tree from top to bottom or from bottom to top. The algorithm quickly eliminated the possibility of collision between objects far apart. And it well adapted to the needs of the dynamic collision detection. Test results showed that the algorithm greatly improved the collision detection’s speed in virtual environment.