Immersive sketch-based tree modeling in virtual reality

Abstract

Tree modeling has been a widely-discussed topic in computer graphics. However, with existing methods, the modeling process is occupied with complex data collection and tedious parameter adjustment, lacking a rich sensory modeling experience. In this paper, we propose an approach to sketch-based tree modeling in an immersive virtual reality environment, aiming to lower the difficulty of modeling and enhance the immersion in the designing process. We first present a sketch sampling and points optimization algorithm to obtain the skeleton of the branch in 3D space. As generating geometry along the skeleton, we apply a vector-projection method to fix the branch polygon twisting. Then, we introduce a bidirectional ray-hit algorithm to determine the branch radius as real-time sketching. To generate random twigs on branches, we introduce a twigs generation algorithm based on Perlin noise and the parent branch direction. Finally, we design a series of interactive methods for users to create tree models in a 3D virtual scene with the VR HMD and controller. Experimental results indicate that our approach can accomplish creating realistic tree models in real-time. The interactive and immersive modeling experience enables users to readily convey their ideas on tree structures in a simple and direct way of sketching. Visualizing and modifying the real-time generated branch results can contribute to provoking the inspiration for creation.