We present a new approach to geometric modeling with developable surfaces and the design of curved-creased origami. We represent developables as splines and express the nonlinear conditions relating to developability and curved folds as quadratic equations. This allows us to utilize a constraint solver which may be described as energy-guided projection onto the constraint manifold, and which is fast enough for interactive modeling. Further, a combined primal-dual surface representation enables us to robustly and quickly solve approximation problems.

No abstract

No abstract

We solve the form-finding problem for polyhedral meshes in a way which combines form, function and fabrication; taking care of userspecified constraints like boundary interpolation, planarity of faces, statics, panel size and shape, enclosed volume, and last, but not least, cost. Our main application is the interactive modeling of meshes for architectural and industrial design. Our approach can be described as guided exploration of the constraint space whose algebraic structure is simplified by introducing auxiliary variables and ensuring that constraints are at most quadratic. Computationally, we perform a projection onto the constraint space which is biased towards low values of an energy which expresses desirable "soft" properties like fairness. We have created a tool which elegantly handles difficult tasks, such as taking boundary-alignment of polyhedral meshes into account, planarization, fairing under planarity side conditions, handling hybrid meshes, and extending the treatment of static equilibrium to shapes which possess overhanging parts.

No abstract

The prokaryotic clustered regularly interspaced short palindromic repeat (CRISPR)-associated system (Cas) is a simple, robust and efficient technique for gene targeting in model organisms such as zebrafish, mice and rats. In this report, we applied CRISPR technology to rabbits by microinjection of Cas9 mRNA and guided RNA (gRNA) into the cytoplasm of pronuclear-stage embryos. We achieved biallelic gene knockout (KO) rabbits by injection of 1 gene (IL2rg) or 2 gene (IL2rg and RAG1) Cas9 mRNA and gRNA with an efficiency of 100%. We also tested the efficiency of multiple gene KOs in early rabbit embryos and found that the efficiency of simultaneous gene mutation on target sites is as high as 100% for 3 genes (IL2rg, RAG1 and RAG2) and 33.3% for 5 genes (IL2rg, RAG1, RAG2, TIKI1 and ALB). Our results demonstrate that the Cas9/gRNA system is a highly efficient and fast tool not only for single-gene editing but also for multi-gene editing in rabbits.Electronic supplementary materialThe online version of this article (doi:10.1186/2045-9769-3-12) contains supplementary material, which is available to authorized users.

We introduce a novel algorithm for isotropic surface remeshing which progressively eliminates obtuse triangles and improves small angles. The main novelty of the proposed approach is a simple vertex insertion scheme that facilitates the removal of large angles, and a vertex removal operation that improves the distribution of small angles. In combination with other standard local mesh operators, e.g., connectivity optimization and local tangential smoothing, our algorithm is able to remesh efficiently a low-quality mesh surface. Our approach can be applied directly or used as a post-processing step following other remeshing approaches. Our method has a similar computational efficiency to the fastest approach available, i.e., real-time adaptive remeshing [1]. In comparison with state-of-the-art approaches, our method consistently generates better results based on evaluations using different metrics.

No abstract