Snabbtangent

Snabbtangent is a term used in numerical analysis and computer graphics to describe approaches for computing tangent vectors to curves and surfaces with low computational cost. The name combines snabb, meaning fast in several Germanic languages, with tangent, reflecting a focus on tangential directions and local linearity.

Concept and methods: Snabbtangent methods typically maintain tangent information as the geometry changes and update it incrementally rather than recomputing from scratch. Key ideas include local linearization, caching of Jacobian-like structures, and stable propagation of small perturbations. Some implementations blend automatic differentiation with selective recomputation to balance accuracy and speed.

Applications: The technique is used in real-time rendering, collision response, physics simulation, and robotics, where fast tangent vectors support shading, contact constraints, motion planning, and constraint solving. It is particularly valued in interactive environments and streaming workflows where latency must be minimized.

Relation to related concepts: Snabbtangent sits alongside tangent space computation, differential geometry, and incremental computation. It is often contrasted with finite-difference approaches, which recompute tangents anew for each change, and with full automatic differentiation, which may incur higher overhead in dynamic scenarios.

History and notes: The term appears in recent discussions and open-source projects exploring optimizations for geometric computations. While not universally adopted, several libraries describe snabbtangent variants as practical tools for real-time geometry processing. Further work analyzes numerical stability and performance trade-offs across workloads.