Nowadays, virtual reality (VR) is becoming an important technique for various educational subjects. However, Chinese calligraphy, as a unique artistic form, remains under-explored in terms of learning in a VR configuration. This deficiency is largely due to the challenge to render delicate haptic feedback of pen and brush during the process of writing. To achieve the purpose of haptic rendering, existing works mostly use the professional device (e.g. Phantom), which is expensive and not accessible to common users. Our work presents a novel yet simple approach to render haptic feedback for Chinese calligraphy in VR by using soft and deformable sponge as the medium between the handheld controller and writing surface. We compared three different feedback configurations using on-device vibration and sponge-enabled haptic feedback against the baseline configuration with no force feedback. Based on both the qualitative and quantitative results from user studies, we found that sponge-based haptic feedback not only provided a comfort experience of interactive virtual writing but also accelerated the learning performance of novices. Our approach is low cost, scalable and produces realistic user experience, which offers an alternative solution for future development of training systems for virtual Chinese calligraphy.

Butterflies are not only ubiquitous around the world but are also widely known for inspiring thrill resonance, with their elegant and peculiar flights. However, realistically modeling and simulating butterfly flights—in particular, for real-time graphics and animation applications—remains an under-explored problem. In this article, we propose an efficient and practical model to simulate butterfly flights. We first model a butterfly with parametric maneuvering functions, including wing-abdomen interaction. Then, we simulate dynamic maneuvering control of the butterfly through our force-based model, which includes both the aerodynamics force and the vortex force. Through many simulation experiments and comparisons, we demonstrate that our method can efficiently simulate realistic butterfly flight motions in various real-world settings.

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