Migrating from potpourri3d

potpourri3d (the Python binding for geometry-central) is the reference for the heat-method family — vector heat, parallel transport, log maps, and signed heat — and ordito's ordito.heat module mirrors that scope. The main structural difference: potpourri3d builds a stateful *Solver object per mesh and reuses it across calls; in ordito the state lives on the mesh: pass an ordito.Trimesh to the heat functions and it keeps their operators and factorizations (its heat_solver) for every later call.

import potpourri3d as pp3d  # before
import ordito as od  # after

Distance and vector heat

potpourri3d	ordito
`pp3d.MeshHeatMethodDistanceSolver(V, F)` then `.compute_distance(source)`	`mesh = od.Trimesh(vertices, faces)` then `heat.heat_geodesic(mesh, sources)`
`pp3d.MeshVectorHeatSolver(V, F)` then `.extend_scalar(sources, values)`	`mesh = od.Trimesh(vertices, faces)` then `heat.extend_scalar(mesh, sources, values)`
`.transport_tangent_vector(source, vector)`	`heat.transport_tangent_vectors`
`.compute_log_map(source)`	`heat.log_map`
`pp3d.SignedHeatSolver(V, F)` then `.compute_distance(curve)`	`heat.heat_signed_distance`
`pp3d.edges(V, F)`	`edges.faces_to_edges` / `edges.edges_unique`
`pp3d.GeodesicTracer(V, F).trace_geodesic_from_vertex(...)`	`geodesic_walk` (straightest geodesics: walk a given distance in a given direction, batched over many walks)
Tangent frames used internally by the solvers	`tangent_space.vertex_tangent_frames` / `face_tangent_frames` (public and directly inspectable in ordito)

What's different, not just renamed

The solver state lives on the mesh, not in a solver object. Where potpourri3d builds a solver per mesh and calls methods on it, ordito's functions take a Trimesh that keeps the operators and factorizations (see Geodesic distance with the heat method); the vertices, faces form keeps nothing between calls.
The defaults discretize differently. potpourri3d's solvers default to use_robust=True, which mollifies the mesh and builds an intrinsic Delaunay Laplacian; ordito defaults to the plain cotangent Laplacian (use_robust=False). To compare the two outputs, construct the potpourri3d solver with use_robust=False, or pass use_robust=True to heat.heat_geodesic.
Tangent-space quantities are gauge-dependent in both libraries. A tangent frame from tangent_space.vertex_tangent_frames agrees with potpourri3d's own frames only up to a rotation about the normal — compare transport results through a gauge-invariant combination (e.g. the angle between two transported vectors), never their raw 2D tangent components, exactly as you would with potpourri3d's own output.
Isolines come back as points, not mesh elements. potpourri3d's marching_triangles reports each isoline point as a geometry-central element index plus barycentric coordinates; ordito's intersection.marching_triangles returns 3D positions directly.