An improved adjacency data structure for fast triangle stripping

To speed up the rendering of polygonal meshes, triangle strips are commonly used to reduce the number of vertices sent to the graphics subsystem by exploiting the fact that adjacent triangles share an edge. In this paper, we present an improved adjacency data structure for fast triangle stripping algorithms. There are three major contributions: first, the data structure can be created quickly and robustly from any indexed face set; second, its cache-friendly layout is specifically designed to efficiently answer common stripping queries, such as neighbor finding and least-degree triangle finding, in constant time; third, the stripping algorithm operates in-place, since strips are created by simply relinking pointers. An implementation of a stripping algorithm shows a significant speed-up compared to other implementations. Our implementation is publicly available as part of OpenSG [9].

The activation of modality in virtual objects assembly

International audienceManual assembly of virtual 3D objects is required in several application fields. We focus on tangible user interfaces which offer the opportunity to the user to perform virtual assemblies efficiently and easily. In each hand, the user manipulates a tracked prop, and the translations and rotations are directly mapped to the corresponding virtual object. However, with such interfaces, both hands are requisitioned, and the user cannot drop the props without changing the action or the expected results. We list and discuss the choice of four possible modalities to activate/deactivate the assembly modality: vocal modality, gestural modality, buttons, and foot pedals. We conclude that when using the foot pedals, the user's gesture is closer to the real-world behaviour

How many fast-charging stations do we need along European highways?

For a successful market take-up of plug-in electric vehicles, fast-charging stations along the highway network play a significant role. This paper provides results from a first study on estimating the minimum number of fast-charging stations along the European highway network of selected countries (i.e., France, Germany, the Benelux countries, Switzerland, Austria, Denmark, the Czech Republic, and Poland) and gives an estimate on their future profitability. The combination of a comprehensive dataset of passenger car trips in Europe and an efficient arc-coverpath-cover flow-refueling location model allows generating results for such a comprehensive transnational highway network for the first time. Besides the minimum number of required fastcharging stations which results from the applied flow-refueling location model (FRLM), an estimation of their profitability as well as some country-specific results are also identified. According to these results the operation of fast-charging stations along the highway will be attractive in 2030 because the number of customers per day and their willingness to pay for a charge is high compared to inner-city charging stations. Their location-specific workloads as well as revenues differ significantly and a careful selection of locations is decisive for their economic operation

Workload patterns of fast charging stations along the German Autobahn

We analyze daily charging demand patterns of electric vehicles at DC fast charging stations along the German autobahn for an average week in 2020. For this we develop an agent based simulation tool based on current empirical mobility data. Our results show that already in 2020 about 1,000 charging processes per charging location and day might be realistic. In order to avoid long waiting times these charging locations should be equipped with about 20 charging points. A utilization rate of up to 80% makes a profitable operation of these stations highly probable. A sensitivity analysis indicates main parameters which influence the throughput of electric vehicles significantly

Reconstruction locale et visualisation de nuages de points par surfaces de subdivision

National audienceLes surfaces de points, qu'elles soient directement acquises par scanner ou issues de la conversion d'autres modèles, permettent de stocker et de transmettre des objets complexes de manière économique, mais sont mal adaptées aux architectures matérielles existantes qui s'appuient sur une description géométrique à base de surfaces polygonales. Cet article propose une technique permettant d'obtenir une visualisation efficace des surfaces de points, entièrement à l'aide du pipeline de rendu matériel. L'idée centrale présentée ici est d'effectuer une reconstruction surfacique locale par triangulation d'un nuage de points, en générant un agrégat de 2-variétés se recouvrant, et en procurant une continuité visuelle dans les zones de recouvrements à l'aide des surfaces de subdivision

Assemblage d'objets 3D Semi-Automatique basé géométrie en Archéologie

8 pagesNational audienceThe recent use of 3D laser scanning in the archaeological context requires techniques and systems to make the generated data usable. In this paper, we focus on the fragment reassembly based on ArcheoTUI, a tangible interface created to assemble the digitals models of fragments manually. We present a semi-automatic system to assist the user in real time in when assembling the fragments. This approach allows to use both the accuracy of geometric algorithms and the scientific knowledge of the archaeologist. The user specifies an approximate initial position of the two fragments by means of the tangible interface. Then, our system performs a real time registration thanks to the use of the Iterative Closest Point registration algorithm combined with a speed-up data structure and a bi-factorial weighting of the pairs. The data structure is used to find an area of interest on each object and to accelerate the pairs generation, whereas the weighting improves the detection of the data relevance