- Surfaces of revolution follow ISO 10303-42 strictly in reader and writer: the
normal is d/d(angle) x d/d(profile), the opposite of truck's revolution, as
Fusion reads it (fixes Fusion inverting fillet sphere corners and the dimple).
step_orientation_errors flags faces whose loop runs clockwise round their
normal; engine, oracle and kernel round trips assert it.
- Revolved faces with analytic profiles are written as native PLANE,
CYLINDRICAL/CONICAL/SPHERICAL/TOROIDAL surfaces, and the pieces truck splits
a revolution into are merged back into one face per surface (with a seam
edge for full turns), so face counts match other systems.
- A horn torus (tight sweep: tube touching its axis) is written as one rational
B-spline face whose loop passes the pole twice, with truck's zero-length pole
edges collapsed, instead of a degenerate surface of revolution; the reader
starts such figure-eight loops off the pole (Fusion's own part 50 now imports
with the right volume).
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
Meshing (vendored truck-meshalgo) works within a budget so hostile files
cannot hang: bounded edge and surface divisions (point caps, depth and
round limits, NaN-safe), and a grid budget per face shared out per shell.
Surface grids refine only the direction that bends; rulings left undivided
get cells comparable to the other direction, so trimmed cylinders (holes,
tee joints) no longer lose volume to long triangles. The helical sweep
imports in 12 s instead of 7 minutes.
Small sphere patches get poles away from them even when the file runs a
seam through the patch (a pyramid's corner blend). Faces the mesher cannot
mesh are reported as import warnings. Test: wild B-spline and far-off
boundaries import in bounded time.
STEP corpus 65/66 (50-sweep-tight-bend: a horn-torus bend whose inner side
collapses to a point; Fusion's own area for it is also off).
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
Vendored truck-stepio (writer only): an intersection curve's second surface
was written at the first one's id (duplicate ids for every boolean edge),
and revolved surfaces lost their orientation (the modeling-surface sense was
always true; inverted or mirrored revolutions came out inside out). Export
now writes intersection edges as C1 cubic B-splines through exact points,
so files carry plain 3D curves and no redundant surfaces.
Vendored truck-meshalgo: hinted parameter searches that run off a B-spline's
domain are rejected or clamped (meshing their grid never finished).
STEP import: straight revolution profiles are bounded in the meridian plane
and stop at the axis; loops on revolutions start away from the axis; face
extents include edge end points. Edges between pieces of one split surface
draw as seams.
kernel::step_validate checks a STEP file (duplicate ids, dangling
references, dense numbering); the oracle replay now exports every rebuilt
part, validates it and re-imports it with no warnings and the same volume
(all 32 rebuildable cases pass).
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
solvecraft-cli step-corpus and cargo xtask step-corpus [DIR]: open every
Fusion oracle part.step and compare body count, volume and area (1e-3) and
face count with Fusion's measurements; docs/step-import.md (29/29 pass).
solvecraft-cli eval/run accept STEP files and --in FILE.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL
