We present a rigid body simulation method that can resolve small temporal and spatial details by using a quasi explicit integration scheme that is unconditionally stable. Traditional rigid body ...simulators linearize constraints because they operate on the velocity level or solve the equations of motion implicitly thereby freezing the constraint directions for multiple iterations. Our method always works with the most recent constraint directions. This allows us to trace high speed motion of objects colliding against curved geometry, to reduce the number of constraints, to increase the robustness of the simulation, and to simplify the formulation of the solver. In this paper we provide all the details to implement a fully fledged rigid body solver that handles contacts, a variety of joint types and the interaction with soft objects.
Projective dynamics was introduced a few years ago as a fast method to yield an approximate yet stable solution to the dynamics of nodal systems subject to stiff internal forces. Previous attempts to ...include contact forces in that framework considered adding a quadratic penalty energy to the global system, which however broke the simple - constant matrix - structure of the global linear equation, while failing to treat contact in an implicit manner. In this paper we propose a simple yet effective method to integrate in a unified and semi-implicit way contact as well as dry frictional forces into the nested architecture of Projective dynamics. Assuming that contacts apply to nodes only, the key is to split the global matrix into a diagonal and a positive matrix, and use this splitting in the local step so as to make a good prediction of frictional contact forces at next iteration. Each frictional contact force is refined independently in the local step, while the original efficient structure of the global step is left unchanged. We apply our algorithm to cloth simulation and show that contact and dry friction can be captured at a reasonable precision within a few iterations only, hence one order of magnitude faster compared to global implicit contact solvers of the literature.
•An interactive simulation is used as a tool for logistics and maintenance processes analysis.•It makes it possible to operate virtual maintenance equipment like cranes, virtual logistics equipment ...like mobile platforms for transport and a manikin representing a maintenance worker.•Features for the analysis of the operations such as clash detection, distance measures and custom defined cameras.•An agile analysis of the planned procedure, clashes and assessment of the design of equipment is presented.
Pre-configured virtual reality (VR) simulations of the logistics and maintenance processes have proven to be useful for identifying potential design issues as well as planning operations during an early design phase of facility. But VR simulations can also be used to deeply explore the feasibility of these procedures in a more interactive manner, so that we can identify potential risks and difficulty levels from early stages and study different maintenance strategies to assist the maintenance worker during these procedures. This article presents a framework to design and validate logistics and maintenance procedures in complex facilities, such as the International Fusion Materials Irradiation Facility DEMO Oriented Neutron Source (IFMIF-DONES). Our framework begins with a preparatory phase where essential information about the procedures and Computer-Aided Design (CAD) models is compiled into a comprehensive Virtualization Task Document (VTD). Differently from previous work, this VTD allows representation of parallel tasks. We implement the interactive version of the virtual environment, where the different maintenance and logistics equipment, as well as a virtual maintenance worker is controlled by the user (the person executing the interactive simulation). We have validated this interactive framework with two simulations for the installation process of the Superconducting Radio Frequency Linear accelerator (SRF Linac) modules in IFMIF-DONES. In one simulation (the automatic one), the procedures are reproduced as they are planned, while in the second simulation (the interactive one) the user freely controls the movements of the moving parts of the crane, grab and release plant equipment, move platforms, etc. Based on our simulations, the interactive version allows easier detection of potential points of collisions as well as more precise assessment of the difficulty of the tasks to be performed.
The mastery of physics and the ability to apply this knowledge may contribute to the development of the country. However, the skills of secondary school students concerning physics are less ...impressive. This exploratory research aims to examine the effectiveness of interactive simulation by PhET as blended learning in physics. The results showed that there was a significant difference in the pre- and post-test mean scores for the experimental group by providing a positive impact on students’ interest, motivation, the pleasure of studying in a group or self-learning, and help to study for exams. This proved that simulation as an aspect of blended learning could improve students’ achievement in physics.
Primal/Dual Descent Methods for Dynamics Macklin, M.; Erleben, K.; Müller, M. ...
Computer graphics forum,
December 2020, Letnik:
39, Številka:
8
Journal Article
Recenzirano
We examine the relationship between primal, or force‐based, and dual, or constraint‐based formulations of dynamics. Variational frameworks such as Projective Dynamics have proved popular for ...deformable simulation, however they have not been adopted for contact‐rich scenarios such as rigid body simulation. We propose a new preconditioned frictional contact solver that is compatible with existing primal optimization methods, and competitive with complementarity‐based approaches. Our relaxed primal model generates improved contact force distributions when compared to dual methods, and has the advantage of being differentiable, making it well‐suited for trajectory optimization. We derive both primal and dual methods from a common variational point of view, and present a comprehensive numerical analysis of both methods with respect to conditioning. We demonstrate our method on scenarios including rigid body contact, deformable simulation, and robotic manipulation.
The study aimed to investigate the effectiveness of using interactive simulation in developing some physics concepts in a sample of kindergarten children. To achieve the study objective, a ...semi-experimental method was used. The study sample consisted of the (45) kindergarten children of ‘The Pink Bird’ Kindergarten in Petra. They were randomly divided into two groups: an experimental group of (22) children who were taught using interactive simulation, and a control group of (23) children who were taught by the traditional way. Contrary to the traditional method of education, the study results proved the effectiveness of interactive simulation in the acquisition of physics concepts among kindergarten children. It was also found that around 61% of the change in the dependent variable (physical concepts) is due to the use of interactive simulation in teaching. Eventually, the study included a set of recommendations in the light of its results.
Parallel and distributed computing enable the execution of large and complex simulations. Yet, the usual separation of (headless) simulation execution and (subsequent, offline) output analysis often ...renders the simulation endeavor long and inefficient. Recently, Visual Interactive Simulation (VIS) tools and methods that address this end-to-end efficiency are gaining relevance, offering in-situ visualization, real-time debugging, and computational steering. Here, the typically distributed computing nature of the simulation execution poses synchronization challenges between the headless simulation engine and the user-facing frontend required for Visual Interactive Simulation. To the best of our knowledge, state-of-the-art synchronization approaches fall short due to their rigidity and inability to adapt to real-time user-centric changes. This paper introduces a novel adaptive algorithm to dynamically adjust the simulation’s pacing through a buffer-based framework, informed by predictive workload analysis. Our extensive experimental evaluation across diverse synthetic scenarios illustrates our method’s effectiveness in enhancing runtime efficiency and synchronicity, significantly reducing end-to-end time while minimizing user interaction delays, thereby addressing key limitations of existing synchronization strategies.
•A holistic dynamic system model is developed to simulate soil salinity and sodicity.•Irrigation efficiency has dual role in salinity control.•Relative intensity of salinity to sodicity impacts ...hydraulic conductivity.•Salt tolerant crops may lead to higher salinization in the long term.•The model is used as the basis of an on-line interactive learning environment.
In this research, a dynamic simulation model, SAMIMI (Salinity/Sodicity Management with an Interactive Model Interface), is developed for managing the effects of agricultural water use and crop choices on soil salinization and sodification, and their impacts on crop yields. SAMIMI integrates the vertical hydraulic flow, solute transport, and crop processes in feedback by a compartmental, non-linear model architecture. With its holistic integrated approach to salinity /sodicity processes, it adopts a system dynamics approach. Though it is simplified in spatial resolution, the model credibility is sufficiently evaluated with indirect structure tests and against the data by Hydrus-1D, and soil-column experiments that were conducted as part of the SAMIMI (Salinity/Sodicity Management Interdisciplinary Multi-Institutional Network) project conducted in the semi-arid Konya Closed Basin of Turkey. Model analysis provide valuable insights to the role of irrigation efficiency, water quality and crop choices on soil degradation and yield losses, which are important for learning about and management of salinity/sodicity related problems: Although irrigation efficiency is desirable for water conservation purposes, it may result in higher salinity /sodicity levels because of insufficient leaching in well drained soil profiles. Salinity and sodicity have opposite effects on soil hydraulic conductivity, and while low saline irrigation water is desirable for agricultural production, under relatively high sodic conditions, it can lead to reduced hydraulic conductivity which can degrade soil characteristics to the detriment of crops. Salinity is not simply correlated with relative irrigation water consumption but with the crop salt tolerance as well. Hence, low water consuming crops with high salt tolerance can lead to over salinization, rendering the soil profiles inappropriate for cultivation of salt vulnerable crops, if not sufficiently leached before by precipitation and/or good-quality irrigation water. The model is published as a publicly available online interactive simulation tool with a fast-simulating user-friendly interface targeting researchers, students, experts, farmers and policy makers.
PhET is one of the most powerful and impressive simulator innovations, widely used in the STEM-based learning process. Based on literature reviews, students are allowed to independently practice ...their skills and understanding of the material concept using this tool. PheT involves students in process competencies comprehensively and also provides a highly interactive virtual environment for STEM materials, including basic electronics, a sub-category of physics. This tool can also be easily accessed online at https://phet.colorado.edu/ or offline with a note that the user should download and install the application on a PC. An interesting question regarding this education tool is, "can PhET support basic electronics learning in Higher Education (HE)?" Numerous preliminary studies have not answered this question, which is associated with the technical aspect of the tool, because they only focused on the pedagogical aspect. Therefore, this research aims to fill this gap by exploring the capability of PhET in simulating basic electronic circuits that were commonly studied by students in HE, including Kirchoff Current Law (Kirchoof I), Kirchoff Voltage Law (Kirchoff II), Voltage Divider, Series/Parallel Resistors, Wheatstone Bridge, and Star – Delta Resistors. These circuits are simulated in two PhET products, namely, online (1.2.7) and offline (3.20) versions, with numerous setups used to compare their performances to the theoretical calculations. Finally, the answers were obtained clearly from the experimental results in the simulation environment.
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