solvecraft/docs/kernel-smlib-sweeps-shell.md

SMLib vs truck: sweeps, threads, shell and offset

A triage of the regression rig's sweeps, threads and shell cases, and of the ladder's tiers 03 (analytic profiles), 04 (spline profiles), 06 (threads) and 09 (shells and offsets): 169 cases, each run on both kernels (solidcraft-cli kernel-cases, SOLIDCRAFT_KERNEL unset and smlib) on kernel-smlib at 4b8953726. Each kernel is graded against the case's own answer (kernel-cases.md), not against the other kernel. This page lists only the cases where SMLib does not pass, grouped by what goes wrong, worst first; it is kept by hand as fixes land.

	Cases	truck passes	SMLib passes
sweeps	83	55	51
threads	28	10	11
shell	18	5	11
ladder 03, 04, 06, 09	40	28	26
all	169	98	99

SMLib passes 18 cases truck fails (shells of tapered and rounded bodies, offset faces next to freeform faces, bent and hollow lofts, the 36 twisted blades). Truck passes 17 that SMLib does not: 11 of them are sweeps SMLib has no path for yet (group G), 6 are below.

A thread off its hole's or shaft's size is refused on this branch (the owner's rule): those cases pass on both kernels by refusing, and are not listed.

A. Wrong geometry (worst)

Case	truck	SMLib	SMLib's result
sweeps/2667-revolve-half-disc-three-quarters	pass	fail	a half disc on the axis turned 270°: SMLib makes a quarter ball turned inside out (V = -226, want 679)
sweeps/3528-revolved-dome-cut-by-a-ball-on-its-seam	pass	fail	the ball's cut is lost where it crosses the revolve's seam: V 48118, want 46425
sweeps/2847-loft-rectangles-turning-through-half-a-turn	fail	fail	inside out (V = -127, want 2262); truck's is wrong too (V = 126)
sweeps/450-revolve-spherical-shell-sketched-off-the-origin	crash	fail	two shells where one is wanted, which the B-rep record can't close (truck's process dies)

B. Crash

Case	truck	SMLib	SMLib's result
ladder/09-shells-and-offsets/011-part-shell	fail	crash	step 21 (solid.fillet) on the SMLib body: curve blend internal error "Two same vertices cannot construct an edge"; the fillet is the blends work's, not this page's

C. Threads: the groove's boolean fails SMLib's check

The groove (SMLib's screw sweep) cuts the body, and the result fails SMLib's own check: vertex gaps of 1–6e-5 mm against vertex tolerances of 4–20e-6 mm (Test #0/#2 Bad Gap), an edge whose geometry fails validation (Test #61), or a trim curve that does not lie on its edge when the result is read back (SMLib export: pcurve). Truck's faceted groove fails SMLib's check on the same cases with 6 to 752 failed tests.

Case	truck	SMLib	SMLib's result
ladder/06-threads/001-external-m10-full	fail	fail	Bad Gap (1.89e-5 > 8.6e-6)
ladder/06-threads/002-external-m10x1-fine	hang	fail	Test #61 bad edge
ladder/06-threads/003-external-m10-partial-length	pass	fail	Bad Gap (1.91e-5 > 8.9e-6)
ladder/06-threads/004-external-m10-to-shoulder	fail	fail	Bad Gap ×10
ladder/06-threads/005-internal-m10-through	fail	fail	Bad Gap (3.6e-5 > 1.8e-5)
ladder/06-threads/006-external-m10-into-chamfer	fail	fail	Bad Gap
ladder/06-threads/007-external-m10-at-filleted-shoulder	fail	fail	Bad Gap
ladder/06-threads/010-part-threaded-boss	fail	fail	Bad Gap (2.26e-5 > 2.0e-5)
threads/1250-external-m10x1.5-shaft-full-length	fail	fail	Bad Gap ×9
threads/1395-long-external-m6-thread-24-turns	fail	fail	Test #61 bad edge
threads/1995-m8x1-thread-in-7mm-hole	fail	fail	Bad Gap (1.5e-5 > 7.5e-6)
threads/2038-cut-threaded-stud-from-bored-block	fail	fail	Test #61 bad edge
threads/2038-internal-then-external-thread-on-one-body	fail	fail	pcurve off its edge
threads/2038-join-two-threaded-bodies	hang	fail	pcurve off its edge
threads/2193-modelled-m33x3.5-thread	fail	fail	Bad Gap
threads/2209-fine-m44x1-thread-on-shaft	fail	fail	Bad Gap ×7
threads/2209-m44x1.5-thread-on-flange-hub	fail	fail	Bad Gap (6.2e-5 > 2.05e-5)
threads/2406-modelled-m8-thread-in-6.8mm-pilot-hole	fail	fail	Bad Gap
threads/2526-three-modelled-threads-in-one-body	fail	fail	pcurve off its edge
threads/2822-modelled-thread-in-filleted-cube	fail	fail	pcurve off its edge
threads/3311-two-tapped-holes-both-modelled-threaded	fail	fail	pcurve off its edge
threads/3914-sketch-on-top-face-of-threaded-rounded-block	fail	fail	pcurve off its edge (0.86 mm)
threads/3952-modelled-thread-in-blind-hole-of-revolved-ring	fail	fail	pcurve off its edge
threads/4149-internal-thread-below-counterbore-filleted-rim	fail	fail	Bad Gap
threads/602-fillet-hex-head-beside-modelled-thread	fail	fail	Bad Gap

D. Coils and other sweeps in booleans

Case	truck	SMLib	SMLib's result
sweeps/793-coil-cut-by-a-box-above-a-plane	hang	fail	pcurve off its edge
sweeps/793-coil-split-by-a-plane-across-its-axis	fail	fail	pcurve off its edge
sweeps/2552-thread-groove-cut-by-a-square-coil-in-a-bore	hang	fail	the boolean's result is not a closed solid
sweeps/96-loft-cut-box-sections-pad-first	fail	fail	the boolean's result is not a closed solid
sweeps/96-loft-cut-box-sections-top-first	fail	fail	the boolean's result is not a closed solid
sweeps/844-join-two-overlapping-swept-arc-walls	fail	fail	boolean status 1006
sweeps/3006-second-sweep-from-a-plane-along-a-closed-path	fail	fail	read back: a face no shell uses

E. Shell and offset refused

Case	truck	SMLib	SMLib's result
ladder/09-shells-and-offsets/006-shell-rounds-r1-thinner-than-t2	pass	fail	shell status 1001 (rounds of r1 inside a 2 mm wall)
shell/1494-shell-box-with-cylinder-on-edge-line	fail	fail	shell status 1001
shell/1525-shell-box-with-rounds-chamfer-and-fillet	fail	fail	shell status 1001
shell/2939-offset-face-sphere	pass	fail	check: edge/surface gap 5.015e-6 > 5e-6
shell/3468-offset-face-boss-wall-next-to-fillet	fail	fail	check: an edge tolerance of 2.0 mm
shell/2531-shell-point-pick-after-parameter-edit	fail	fail	V 17952, want 22112 (truck 17376): the shell's face pick after the edit, on both kernels
sweeps/2820-pipe-hollow-with-a-wall-along-a-bend	pass	fail	sweep status 1001

F. Same answer on both kernels (engine or case)

Case	truck	SMLib	Both kernels
sweeps/3345-sweep-profile-mid-line-round-a-rounded-rectangle	fail	fail	the same bbox (±46 × ±36, want ±32 × ±22): the profile's placement, not the kernel
sweeps/2516-revolve-about-a-named-construction-axis	fail	fail	unknown sketch line Axis1
sweeps/3191-revolve-cut-leaves-a-cone	fail	fail	the profile crosses the revolve axis
sweeps/4056-surface-loft-rails-…-stern-to-bow	fail	fail	a guide rail misses section 2
sweeps/2570-loft-circle-to-a-non-star-shaped-comb	fail	fail	SMLib: an arc turns more than once; truck: a loop runs clockwise
shell/4009-closed-shell-internal-void	fail	fail	solid.shell needs 1…1000 faces (a closed shell has none)
ladder/06-threads/008-multi-start-thread	unsupported	unsupported	no start count yet
ladder/06-threads/009-thread-runout-length	unsupported	unsupported	no runout length yet

G. No SMLib path yet ("not supported yet", never truck's in its place)

What	Cases
sweep with a twist or an end scale	sweeps/1269-sweep-twisted-square-ninety-degrees, 2005-closed-sweep-twisted-new-body, 2005-closed-sweep-twisted-cut-inside-a-torus, 2891-twisted-sweep-cut-through-a-tube, 771-sweep-end-scale-cone-frustum
sweep along a path with corners	ladder/04/003-pipe-along-bezier, ladder/04/004-sweep-square-along-bezier, sweeps/96-sweep-rectangle-round-a-mitred-corner, 561-extrude-the-end-face-of-a-sweep, 3505-extrude-the-flat-wall-of-a-sweep-with-a-corner
loft through sections with holes	sweeps/1184-loft-ring-sections-keep-the-hole, 2435-loft-rectangular-ring-sections, 3111-loft-rectangular-ring-to-circular-ring
guide rails	sweeps/201-loft-one-guide-rail-cone-frustum, 771-sweep-one-guide-rail-cone-frustum, 771-sweep-two-guide-rails-cone-frustum
sweep along a path of points	sweeps/2862-three-pipes-meeting-at-one-point
draft extrusion with a straight foot	shell/391-deboss-text-on-flange-of-filleted-shelled-body