Performance

Hot spots

• Nearest-triangle search / projection: use a persistent cell locator.

• Collision checks: batch inserts and rebuild the KD-tree periodically.

• Step size: large steps cause retries; too small steps waste iterations.

Practical tips

• Reuse locators: create the VTK cell locator once per mesh, reuse in all steps.

• Batch updates: call Nodes.update_collision_tree() after a batch of nodes, not every node.

• Tune step: choose l_segment so that length / l_segment is ~10–30 segments.

• Avoid tiny angles: very small branch_angle increases projection/collision retries.

• Vectorize: where possible, operate on arrays; avoid Python loops in tight paths.

Scaling out

• Separate runs with different seeds/params across processes.

• Persist intermediate outputs (nodes/connectivity) if activation is separate.

Diagnostics

• Log: number of retries due to collisions, number of branch terminations, average segments per branch.

• Track: max nearest-node distance over time (surface coverage proxy).