Browsing by Author "Kavan, Ladislav"

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    Fast Simulation of Deformable Characters with Articulated Skeletons in Projective Dynamics
    (ACM, 2019) Li, Jing; Liu, Tiantian; Kavan, Ladislav; Batty, Christopher and Huang, Jin
    We propose a fast and robust solver to simulate continuum-based deformable models with constraints, in particular, rigid-body and joint constraints useful for soft articulated characters. Our method embeds degrees of freedom of both articulated rigid bodies and deformable bodies in one unified optimization problem, thus coupling the deformable and rigid bodies. Our method can efficiently simulate character models, with rigid-body parts (bones) being correctly coupled with deformable parts (flesh). Our method is stable because backward Euler time integration is applied to rigid as well as deformable degrees of freedom. Our method is rigorously derived from constrained Newtonian mechanics. In an example simulation with rigid bodies only, we demonstrate that our method converges to the same motion as classical explicitly integrated rigid body simulator.
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    Seamless Reconstruction of Part-Based High-Relief Models from Hand-Drawn Images
    (ACM, 2018) Dvorožnák, Marek; Nejad, Saman Sepehri; Jamriška, Ondřej; Jacobson, Alec; Kavan, Ladislav; Sýkora, Daniel; Aydın, Tunç and Sýkora, Daniel
    We present a new approach to reconstruction of high-relief models from hand-made drawings. Our method is tailored to an interactive modeling scenario where the input drawing can be separated into a set of semantically meaningful parts of which relative depth order is known beforehand. For this kind of input, our technique allows inflating individual components to have a semi-elliptical profile, position them to satisfy prescribed depth order, and provide their seamless interconnection. As compared to previous similar frameworks our approach is the first that formulates this reconstruction process as a joint non-linear optimization problem. Although its direct optimization is computationally demanding we propose an approximative solution which delivers comparable results orders of magnitude faster enabling an interactive response. We evaluate our approach on various hand-made drawings and demonstrate that it provides stateof-the-art quality in comparison with previous methods which require comparable user intervention.