DeviceSdf gains `tip_corner: Option<f64>` (None = the capsule, as before;
Some(r_c) = a FLAT tip through the centreline's last point, normal to the
last segment, corners rounded to r_c): the last segment becomes a ray for
the lateral distance and the strip is cut by the tip plane with the span
cut's rounded intersection. Host twin (plate.rs: closest/tip_axial/
flat_cap, polyline and plate bodies) and the device φ and velocity
(e3_geom.cu geom_phi_at / body_velocity / plate_dist; GeomSdf flat_tip +
tip_corner) expression for expression.
Knobs: flag test RTX_E3_FLAG_TIP=flat + RTX_E3_FLAG_TIP_CORNER (default
0.00125 m; the tip inset defaults to 0 with the flat tip; the host φ is
the device form's); R8-a harness RTX_E3FSI_TIP=flat + RTX_E3FSI_TIP_CORNER
(the centreline gains node A as a 36th station).
New host test embedded3_flat_tip (G2 geometry: tip plane at the last
point, r_c = half = the capsule pulled back by half to 4e-17, cut volume
and wall area vs the analytic rounded rectangle at ny 62/124/248).
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
