The shaded surface of a curved solid was visibly coarser than its own
wireframe: the wire ran along the true rim while the facets cut inside it.
Two things were wrong, and only one was the tolerance.
`facet_res` is a resolution multiplier — the same one `scale_lod` divides the
fallback sampler's chord fraction by — and the kernel path was using it as a
sag in world units. At the default that asks for a whole unit of departure, so
nothing smaller than a metre subdivided at all and a face was only ever as
round as its own boundary. It is a fraction of each surface's own radius now,
which carries no assumption about the drawing's units.
And it is the *edges'* fraction, shared from `EDGE_CHORD_FRAC` rather than
copied. Those edges are drawn over these faces; sampling the two differently
is what put the wire across a facet instead of along its corners. `facet_res`
is deliberately not applied either, since the edges it must line up with are
built once at highest detail and never scaled.
A torus is measured by its tube rather than its ring — the tube is the tighter
bend, and sampling to the ring leaves the section a hexagon.
The primitive-volume test claimed a mesh can never read over its true size.
That holds for a convex solid, where every chord lies inside; a torus is not
one, and across the inside of its tube the chords fall outside the material.
It passed before only because the sampling was too coarse to show it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Faces were being dropped for sitting a nanometre off their own plane.
An edge is shared by two faces and in a real file cannot lie exactly on both:
the two surfaces were fitted separately and written to finite precision. Asked
for exactness, the kernel decides the edge is not on its plane, declines to
project it, and the face goes undrawn — silently, since a face that cannot be
expressed is reported as absent rather than as an error.
A micrometre in a drawing measured in metres recovers twenty-six walls of one
building. Loosening further buys almost nothing — a hundredth of this finds
one more face in sixty thousand — and past that it would start accepting
geometry that really is wrong, so it stops here.
With the tube fix that came with the kernel bump, VILLA_NEU_IFC3.dwg now
meshes 59015 of its 59033 faces, from 58922.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Solids in a BIM export collapsed onto the origin — every one the right shape,
all in the same place.
ACIS keeps a body's geometry in its own local frame and records where it sits
in a separate `transform` record. Both paths that drew ACIS before this
applied it; the kernel path I put in their place did not, so every solid drew
at its local origin. A file authored in absolute coordinates carries no
transform and looked fine, which is why it took a placed one to show.
The mesh now goes through `finalize_mesh`, which already applied the placement
for the fallback sampler and already split positions into the coarse and fine
pair. That fixes the fault and deletes the hand-rolled copy of the splitting
next to it.
The convention is the part worth testing and the part that invites a mistake:
ACIS treats points as row vectors, `p' = scale·(p·M) + T`, so the stored 3×3
is indexed transposed from a column-vector multiply and the translation is not
scaled. Getting the first wrong mirrors a solid instead of moving it; the
second puts it at twice its offset, which reads as a plausible position and is
the wrong one. Both are covered.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Every 3-D solid OCS makes or opens now goes through cadkernel, which holds
analytic surfaces — a cylinder is a cylinder record, not a spline that looks
like one. That is what lets a solid built here be written back out as exact
ACIS instead of a triangulation, and a facetted export is a one-way door: the
next application to open the file would have no way back to the circle.
The Model tab's seven primitives, the Design-group booleans, 3DROTATE,
3DMIRROR, 3DALIGN, SLICE, SECTION, POLYSOLID and PYRAMID all come from the
kernel now, and `scene.solid_models` holds a `Body`. A mirrored solid needed
its own care before; the kernel reverses the loops on the way through, so it
comes back the right way out rather than lighting black.
EXTRUDE and REVOLVE sweep the profile `entities::curve` already defines, so a
circle, an arc-bulged polyline and a closed spline arrive as the same thing.
A circle extrudes into four cylinder patches rather than a run of chords, and
a profile turned about an axis becomes a cone, a sphere or a torus. A spline
profile has no analytic side wall and is refused rather than approximated.
ACIS goes both ways through the codec's own bridge: `lift` to read and
`append` to write. That drops the 679-line truck conversion and the planar-
only exporter, and the tessellator keeps its bespoke sampler as a fallback for
whatever the kernel cannot yet express — reported rather than passed off as
whole, since a mesh missing a wall looks finished.
truck-shapeops is no longer used and is gone from the manifest. truck-modeling
stays for now: fourteen files use it as a 3-D NURBS evaluator, which the
kernel has no answer for yet, and SWEEP and LOFT have no kernel operation
behind them either.
The two `automation` test failures are unchanged from before this and are not
caused by it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
ramox81