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cad-kernel

CAD geometry kernel

Parasolid, Open CASCADE

SystemTechniques · 8Primitives · 14 cad-kernel B rep topologygeometry · medium: Boundary representation: solids as shells, faces, loops, edges and vertices with geometry attachedDelaunay triangulationgeometry · medium: Bowyer-Watson and incremental flips; maximizes minimum angles, dual of VoronoiGeometric constraint solvinggeometry · medium: Solve sketch constraints (distance, tangent, parallel) by graph decomposition and Newton iterationNurbsgeometry · medium: B-splines and NURBS curves and surfaces: knot vectors, de Boor evaluation, knot insertionPolygon tessellationgeometry · medium: Triangulate polygons with holes (ear clipping, earcut, monotone sweep)Solid boolean operationsgeometry · medium: Union, intersection and difference of solids: classify, split and merge faces robustlySurface surface intersectiongeometry · medium: Intersect parametric surfaces by marching with subdivision and Newton refinementExact geometric predicatesgeometry · low: Robust orient and incircle tests with adaptive-precision floats (Shewchuk) or exact arithmeticHalf edge meshgraphics · low: Half-edge mesh connectivity for editable polygon meshesNewton root findingnumerics · low: Linearize at the guess and jump to the tangent root; quadratic convergence near a simple root, made robust by brackets (1D) or line search.›Bézier curvesgraphics · low: Smooth curves defined by 3-4 control points, evaluated and split with repeated linear interpolation (de Casteljau) and flattened to lines with a closed-form segment count.›Bounding volume hierarchyphysics · low: Binary tree of nested bounding boxes; prunes overlap and ray queries to O(log n) for any size distribution, and supports cheap insert/remove for moving objects.›Interval arithmeticnumerics · low: Rigorous bounds with outward rounding; root isolation and robust geometric testsFloating-point errornumerics · low: How IEEE 754 rounding error accumulates and how to contain it: compensated (Kahan/Neumaier) and pairwise summation, error-free transformations with FMA, ULP comparisons.›Space filling curvesgeometry · low: Z-order/Morton (geohash) and Hilbert curves mapping multi-dimensional points to sortable keysStrongly connected componentsgraphs · low: Tarjan/Kosaraju SCCs for cycle detection in dependency graphsSpline interpolationnumerics · low: Linear, bilinear/trilinear and cubic spline interpolation on grids and tablesFinite differencesnumerics · low: Replace derivatives with weighted differences of grid values; simple stencils plus a stability condition (CFL) turn PDEs like heat, advection and waves into array loops.›LU and Cholesky factorizationnumerics · low: Factor A = PLU (any square matrix, partial pivoting) or A = LLᵀ (SPD) once in O(n³), then solve each right-hand side in O(n²).›Explicit Eulernumerics · low: Step an ODE forward by its current slope, y += h·f(t, y); first-order, one evaluation per step, the baseline every other integrator is measured against.›Thomas tridiagonal solvernumerics · low: O(n) tridiagonal linear solve used in implicit finite-difference and spline schemes+ 1 more techniques

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