Two places were left describing geometry for themselves.
A fit-point SPLINE was drawn from a C² cubic solved in spline.rs while
TRIM and snap cut a separate interpolation from the kernel. Near enough
to look right, far enough apart that a trim landed beside the line it
was aimed at. It now draws the curve those commands work on, and falls
back to the local solve only where the kernel declines — a fit spline
through points in space is not a planar curve, so there is nothing for
it to say.
Closed fit splines were worse than that: the kernel's interpolation is a
clamped solve with no wrap in it, so the curve TRIM used never returned
to its start and the seam cut nothing. Repeating the first fit point
closes it. The seam is C¹ where the rest of the curve is C², which is
the honest limit of a clamped solve — the alternative was a curve with a
gap in it.
OFFSET's preview sampling had drifted the same way TRIM's had: an arc
and a circle read `center.x/.y` as world coordinates when the entity
stores them in its OCS, so an extruded one previewed on the wrong side;
every curved kind was cut at a fixed twenty segments per radian whatever
its size; and an ellipse rebuilt its axis frame from the major axis' X
and Y alone, dropping the Z the entity stores. A hundred lines of that
become one tessellation. A RAY now previews as far as an XLINE does
rather than as a stub the length of its direction vector.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The point lists were built three different ways and none of them scaled
with the geometry. A full ellipse was cut into sixteen segments per half
and an elliptical arc into thirty-two, whatever its size, so anything
large read as a polygon; a circle worked out its own segment count from
the chord tolerance; an arc was handed to truck's arc-through-three-
points builder, which cancels at survey coordinates.
All three now sample the entity's curve at the render pass's chord
tolerance, so how round something looks follows how big it is and how
far in the view is zoomed. The ellipse also stops casting its local
coordinates to f32 on the way in — the vertex path splits f64 into a
double-single pair precisely so that precision survives to the shader,
and throwing it away first defeated that.
What does not change is the kind of object each entity hands over.
EXTRUDE, REVOLVE and SWEEP read their profile and path out of Contour or
Curve and have no arm for a bare point list, so an arc or an ellipse
given as Lines would quietly stop being usable as either. The arc keeps
its circle_arc edge for that reason; only the ellipse's control points
change, and they keep the same two-half-edge wire.
The ellipse now decides it is closed from its own endpoints rather than
from its stored parameters, so a file that writes an end a hair short of
a full turn still produces a wire a plane can attach to.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The same shape was being read out of an entity's fields in three places
and the three had drifted. An arc's tessellation cut it at 20 segments
per radian, TRIM's sampling at 16, and its snap points came from a
fourth expression again; a spline was sampled at a fixed 96 points
however long it was; TRIM read an arc's centre as world coordinates
when the entity stores it in its OCS, so an arc carrying the (0, 0, −1)
normal a MIRROR leaves behind acted as a boundary on the wrong side of
the drawing.
entity_curve returns a PlanarCurve: the shape, plus the plane its
coordinates are read in. The plane comes from the entity's OCS — its
extrusion normal through the DXF arbitrary-axis algorithm — not from the
UCS. A UCS is the working plane a user drew in and an entity does not
remember it: draw a circle in a UCS turned 30° about Z and the stored
normal is still +Z, which is why the header keeps the UCS separately.
The algorithm itself stays in transform.rs, where the format is
understood and where #142's degenerate case was fixed once.
Entities that store world coordinates and may not be planar at all —
LINE, SPLINE — are checked rather than assumed. A spline whose points
wander in space returns None instead of being flattened onto XY, which
would move it.
entity_curve_xy folds the plane away for the editing commands, which
work in plan view and need every boundary in one frame before two of
them can be intersected.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
