Path, mesh, and surface morphing
Correspondence first
Morphing requires correspondence: the interpolator must know which source element becomes which target element. KineticKit validates this relation before animation.
Paths
Compatible paths interpolate command coordinates directly. When paths need normalisation, curved segment length is approximated, split parameters are chosen by arc-length fraction, and de Casteljau subdivision adds corresponding segments. For matched control points \(P_i\) and \(Q_i\),
This preserves exact endpoints and command topology at every intermediate frame.
Meshes
Meshes with matching faces interpolate vertex arrays componentwise. If \(V_0,V_1 \in \mathbb{R}^{n \times 3}\) share topology, then \(V(u)=(1-u) V_0+u V_1\). An explicit correspondence can permute vertices when semantic identity differs from storage order.
Height-field surfaces
A regular surface samples \(z=f(x,y)\) on a grid. Morphing keeps the \(x,y\) lattice fixed and interpolates height and optional colour data. Camera motion remains independent, so a surface morph and orbit can run concurrently with with_().
Path2D(commands)An immutable sequence of exact move, line, Bézier, and close commands used by 2D paths and shapes.
MeshData(vertices, faces, normals=None, colors=None)Validated vertices, faces, and optional correspondence data for mesh interpolation.
SurfaceGrid(points)A regular \(x,y\) lattice with height and optional colour samples for surface morphing.
Morph or transition
Use a SceneTransition cross-fade only when the objects really differ; use morphing when intermediate geometry has meaning.