The static simulation of weft knitting can be efficiently realized by graphics simulation techniques, but there still remains a challenge for mechanical models. The lack of practical mechanical ...models significantly limit the realistic deformation behaviors of complex cable stitches, which lead to a great different between the simulation effect and the actual fabric. In order to obtain the deformation behavior and volumetric performance of cable stitch, loop models were built based on an improved particle system in this work. Compared with plain weft knitted, the offset value of bonding points of cable stitches were measured. By analyzing the relationship between the deformation of loops and the displacement of the particles, the deformation behavior of cable stitch was simulated. Velocity-Verlet integration was introduced to simulate cable stitches and the stable results were obtained. The results show that these models and algorithm displayed the accurate deformation behavior of cable stitches, as demonstrated by qualitative comparisons to measure the deformations of actual samples.
Managing crowds is a key problem in a world with a growing population. Being able to predict and manage possible disasters directly affects the safety of crowd events. Current simulations focus ...mostly on navigation, but crowds have their own special characteristics and phenomena. Under specific conditions, a mass can turn into a crowd turbulence which may lead to a possible disaster. Understanding the internal phenomena is an important issue in order to model behavior. In the particular case of crowd turbulence, agents are moved by the crowd by a series of pushes, an involuntary movement that can be hard to reproduce. We propose a simple model to implement this complex problem based on intentional and involuntary interactions among the agents. The implementation is a hybrid model between the Verlet integration method and Agent Based Modeling. We implemented the proposed model using C and OpenCL and we evaluated its performance on a Nvidia GPU.
Cloth simulation is a significant technique of physical animation, which can produce realistic cloth animation. However, previous methods scarcely generate convincing garment animation in real time, ...and require much numerical calculation. In this paper, we introduce an original algorithm, which reduces requisite simulation springs by half, guarantees expeditious numerical evaluation. The Verlet integration is used for describing kinetic springs which are substructures of deformable objects. After that, we do the collision handling by AABB collision detection and response. Finally handled quantitative data of garment and virtual character animation are delivered to rendering pipeline for displaying. This system provides corresponding APIs which offer distinct geometry simplification methods and collision properties. It is convenient for users to adjust environment parameters and observe rendering effects. Our method is efficacious and straightforward to achieve acceptable simulation effects without complex processing.
In order to simulate the whole process of acupuncture treatment, we put forward a methodology based on improved mass-spring model to simulate the skin rotation by using method of Mathematical ...Physics. Firstly, we simulate the subsidence of skin when the acupuncture needle exerts external force on the skin by using the improved mass-spring model. And then, we adopt Verlet integration to update mass points' position and draw dynamic deformation of the skin when the skin mesh re-gains balance. Finally, we implement the simulation experiments in the OpenGL environment. Experimental results show that the methodology we present can simulate the skin rotation deformation realistically and well meet the requirement of real-time.
As minimally invasive surgical techniques become widely available to patients, medical training systems based on virtual reality (VR) are highly desired. These systems help surgeon trainees to ...acquire, practice and evaluate their surgical skills. A key component in a VR-Based training system is to simulate the dynamics that occur in surgical procedures. Tissue deformation, as a most common phenomenon during surgery, has attracted many research efforts in computer simulation. In this paper, we propose an improved mass-spring model method aiming at realistic simulation of tissue deformation and reduced computational complexity. First, virtual springs are proposed which, along with the conventional mass-spring model, to represent the tissue surface. Second, Verlet integration is adopted to calculate the position of mass points during deformation without explicit computation of their velocities. Finally, a bilinear interpolation method is employed to generate a smooth mesh to render the deformed tissue surface. The proposed method has been implemented using OpenGL which generates realistic tissue deformation images in real-time.
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