SUMMARY: VTX is a molecular visualization software capable to handle most molecular structures and dynamics trajectories file formats. It features a real-time high-performance molecular graphics engine, based on modern OpenGL, optimized for the visualization of massive molecular systems and molecular dynamics trajectories. VTX includes multiple interactive camera and user interaction features, notably free-fly navigation and a fully modular graphical user interface designed for increased usability. It allows the production of high-resolution images for presentations and posters with custom background. VTX design is focused on performance and usability for research, teaching, and educative purposes. AVAILABILITY AND IMPLEMENTATION: VTX is open source and free for non-commercial use. Builds for Windows and Ubuntu Linux are available at http://vtx.drugdesign.fr. The source code is available at https://github.com/VTX-Molecular-Visualization.

We present a novel comprehensive construction algorithm of Apollonius diagrams designed for GPUs. Efficient and robust algorithms have been proposed for the computation of Voronoi diagrams or Power diagrams. In contrast, Apollonius cells are neither convex nor bounded by straight boundaries, making their computation complex, especially in more than two dimensions. Their parallel computation also represents a challenge because of the sequential nature of state-of-the-art algorithms. In this article, we tackle the computation of these diagrams from the geometry of their cells. Our strategy is based on a core cell topology update allowing the iterative insertion of new sites found through nearest neighbor queries. To benefit from the highly parallel environment of modern GPUs and fit their memory restriction, we define a lightweight data structure allowing the representation of the complex topology of Apollonius cells. Additionally, we provide several space exploration procedures for their efficient construction under both homogeneous and heterogeneous spatial distributions. Our method outperforms the fastest state-of-the-art CPU implementation while computing the complete geometry. As a possible use case, we show an application for molecular illustration.

The Solvent-Excluded Surface (SES) is an essential representation of molecules which is massively used in molecular modeling and drug discovery since it represents the interacting surface between molecules. Based on its properties, it supports the visualization of both large scale shapes and details of molecules. While several methods targeted its computation, the ability to process large molecular structures to address the introduction of big complex analysis while leveraging the massively parallel architecture of GPUs has remained a challenge. This is mostly caused by the need for consequent memory allocation or by the complexity of the parallelization of its processing. In this paper, we leverage the last theoretical advances made for the depiction of the SES to provide fast analytical computation with low impact on memory. We show that our method is able to compute the complete surface while handling large molecular complexes with competitive computation time costs compared to previous works.

MOTIVATION: Protein-protein docking aims at predicting the geometry of protein interactions to gain insights into the mechanisms underlying these processes and develop new strategies for drug discovery. Interactive and user-oriented manipulation tools can support this task complementary to automated software. RESULTS: This article presents an interactive multi-body protein-protein docking software, UDock2, designed for research but also usable for teaching and popularization of science purposes due to its high usability. In UDock2, the users tackle the conformational space of protein interfaces using an intuitive real-time docking procedure with on-the-fly scoring. UDock2 integrates traditional computer graphics methods to facilitate the visualization and to provide better insight into protein surfaces, interfaces, and properties. AVAILABILITY AND IMPLEMENTATION: UDock2 is open-source, cross-platform (Windows and Linux), and available at http://udock.fr. The code can be accessed at https://gitlab.com/Udock/Udock2.