Shape-Controllable Smoke Animation

Smoke control animation has always been one important branch in the field of fluid simulation, and controllable smoke animation has been more and more widely used in the design of special effects in the film-making and advertising industry. The approach of making animations or videos by applying computer simulation technologies has not only unshackled animators and directors, giving full play of their unrestrained imaginations, but also saved a lot of cost for shooting videos in film-making industry and other related entertainment domains. Meanwhile, it has greatly reduced the risks of actors being exposed in hazardous scenes and getting hurt. Due to this huge application value, smoke control animation has attracted a lot of attention from many researchers and much effort has been put into this field.This study presents a detailed analysis of the state-of-the-art methods in smoke ani-mation, and offers an in-depth exploration of several key problems in the field of smoke control animation. Solutions are given in a systematic way. To be specific, the dissertation has the following contributions:● Smoke control involves shape and path. A unified framework able to deal with both of them will enable animators to manipulate the shape and path of smoke anima-tion more effectively. In this paper, we develop such a unified framework. With our approach, path control, shape control, and mixed control of both can be handled satis-factorily in the same framework. In order to develop this framework, we use a signed distance field to provide three control forces:path control force, boundary control force, and shape control force based on medial axis point clouds. The path control force makes the smoke move along the appointed route, the boundary control force keeps the smoke moving through specified regions only, and the shape control force enables the smoke to form various given shapes. The boundary control force and the shape control force are two novel control forces developed in this paper. To make the smoke form the target shape more accurately, we develop an adaptive strategy to adjust the divergence field. We also employ a new hybrid vortex particle scheme to enhance the turbulence flow details. The examples given in this paper indicate that our proposed framework is advantageous over the existing shape control approaches and path control algorithms, and a naive combination of the two.● When creating controllable smoke animation, animators often need to adjust various parameters to achieve a satisfactory effect. Therefore, a fast and efficient computing framework will improve the efficiency of animators and save their design time. To this end, we present a novel computing framework to create the animation of con-trollable smoke. Under this new computing framework, a Poisson equation algorithm based on DST has been employed to replace the traditional PCG algorithm. In addi-tion, an improved vortex particle algorithm has also been introduced to both enhance turbulence details and get the solution of convective teams in fluid equations. Experi-ments show that the presented framework is about 20 times faster than the traditional framework while producing similar results.● We present a novel procedural synthesis method to improve small-scale turbulence details for controllable smoke animation constrained by shapes and paths. In order to enhance fluid details without introducing unpleasing fluid control effects, we propose a spatial-temporal varying synthesis parameter to control turbulence behaviors, and compute it from control force and the vorticity velocity. Our approach can control enhanced turbulence behaviors efficiently and produce visually plausible realistic fine-scale details while reducing artifacts of large-scale noises on fluid control. We compare our algorithm to existing procedural synthesis ones to validate its efficiency and controllability.