Function fillet_edges 

pub fn fillet_edges(
    model: &mut Model,
    solid: &Shape,
    edges: &[Shape],
    radius: f64,
    tol: Tolerances,
) -> OgeomResult<Built>

Round a chain of edges in one call, each blend applied in turn and every later edge resolved through the history the earlier blends wrote.

A solid bounded by planes, each face one ring of straight edges, goes first through the blend engine (docs/adr/0001-blend-architecture.md), which builds the whole request in one pass, the same solid in any order. Every face is set back to where its rounds’ contact lines meet. Every round is its exact cylinder between them, ended through its faces’ setback corners (skew on the cylinder where they stand at different stations). A vertex closes as a sphere where one ball touches its three faces there, flush in its third face where one round ends square to it, and otherwise with one transfinite patch tangent to the three rounds’ ends within the bands’ fit target. Every face is proved within the material it rounds. A request the engine does not take (curved faces, a face set back to a line, a vertex of four edges, an edge’s two ends set back past each other) is rounded as follows.

At a tangent junction the neighbouring wedges’ end caps stand in one plane with one cross-section, and the boolean’s same-domain resolution melts them: the blends join without a seam face between them. Two convex edges of the chain that share a face and turn at a vertex meet there, the way one edge at a time (fillet_edge) deliberately does not, since the flush-ended state is what the corner tool (round_vertex) is built for. Carried on past the vertex, each band is a straight band of its end section, and two of one radius cross in the plane through the meeting of their centre lines that bisects them, where the reflection in that plane carries the one band’s end section onto the other’s (the shared host flat, the two walls’ tangent planes at the vertex reflections of each other, to the fit a marched band is held to). Across a re-entrant turn (an L-shaped top’s inside corner) both then run on past their caps to that plane, taking the corner cell they both hold, where the material holds that cell; across a convex turn of a curved crease both stop in it where the bands’ own curvature keeps their sections there within that fit. Either way the two are built from the solid as it stands and joined across the plane into one wedge, each band’s faces credited to its own edge. Where the end sections differ (a drafted wall beside a square one) and both creases are straight, across a re-entrant turn the corner takes what lies above both bands carried on, bounded by the boolean’s own intersection of the two, where the material holds it all. Across a convex turn of two straight creases, whatever their sections, each band runs out past the vertex as it does alone and the cuts take their union (walls leaning alike with their feet out each reach past the bisecting plane under the other’s band, which a meeting there would leave standing), as they do where one of the two is a drum’s rim (a D-shaped block’s arc beside its chord, and past where they meet flush, a rib’s spline wall running into a boss’s rim). Across a re-entrant turn one of the two may be a drum’s rim, upright or drafted, the material within the drum, where the straight band carried on stands nowhere off the drum before the rim’s cap. Such junctions stand beside flush ones in a loop or chain, a band crossed at both ends cut in two halfway along, and two bands meeting at both their ends meet at each. Elsewhere (a wider convex turn of two curved bands, or of a curved band other than a drum’s rim beside one of another kind) and wherever the meeting does not close, the later seat runs on through the earlier blend’s band and the cut trims the two bands against each other along their own intersection, or the caps stand, as without a junction. Where three or more edges of the chain meet at one vertex, the corner tool closes it with the rolling ball’s own patch (the octant of a sphere at a box corner, the envelope of spheres and cylinders at a vertex no single ball touches) rather than leaving the bands’ caps standing. The corner goes first and the bands stop flush against its patch: bands built first crash into each other at an apex. A corner the tool does not speak (a concave vertex, more than three surfaces with no shared ball when one of them is curved) keeps its caps, which is the honest picture of a corner no ball rolls around. Two creases meeting on no shared face leave the wedges’ caps standing likewise.

Only two blends that round the same way trim each other. A wedge’s cut would eat a fill, and a fill cannot run on through a wedge’s band, so where a convex edge meets a concave one (an L-bracket’s front edge at its re-entrant edge) no ball rolls round both. There the request is rounded in one order whatever its own, and a vertex of three planar faces and three straight edges, all of them asked, is closed as round_vertex_setback closes a corner: each band stopped one of its own widths past the least setback at which its section clears the others, and one patch G1 to every band end and face, the same solid in any order.

What solid shares with other shapes is copied before it is worked on (ogeom_algo::on_own_nodes), which leaves them as they are.

Errors

As fillet_edge per edge, and additionally if an earlier blend consumed or split a later edge: a chain whose members interfere is refused rather than guessed at. Where a convex and a concave edge of the request meet at a vertex that is not three planar faces and three straight edges, all asked or one left sharp and convex, the request is refused by name in any order, and so where a band’s setback reaches its edge’s far end or the corner’s cell reaches through the solid behind the vertex. A request of two or more edges also refuses a ball that sets back past the far side of a face anywhere along an edge that shares a face or a vertex with another of the request, since each band’s contacts are checked against the others’ and a contact off its face holds none to check. An edge sharing neither is held to what fillet_edge holds it to.