Function remesh 

pub fn remesh(
    tx: &mut Transaction<'_>,
    options: &RemeshOptions,
) -> Result<RemeshReport>

Remeshes the edges inside options.region toward the target length.

Each round splits the edges whose midpoint lies in the region and whose length exceeds the target by SPLIT_FACTOR, collapses interior edges shorter than the target by COLLAPSE_FACTOR, and flips interior edges whose quad gains a larger minimum angle. Splitting an edge inserts one vertex at its midpoint, shared by the triangles on either side, so neighbors stay stitched; collapsing an edge merges its endpoints into one midpoint vertex. Boundary edges never collapse, and any pass that would fold the surface is skipped. The whole plan is computed on working copies first and committed through tx at the end, which keeps the call atomic under sweep: either every round lands or nothing does.