Arc: tessellates bottom + top arcs (32 segs each) with 2 endpoint walls.
Circle: tessellates bottom + top circles (64 segs each) with 4 quadrant walls.
Both use TruckObject::Lines with NaN-separated segments.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Entities carrying a non-standard extrusion normal (normal ≠ (0,0,1)) were
rendered flat in the XY plane. The DXF arbitrary-axis algorithm is now
implemented in scene::transform::{ocs_axes, ocs_point_to_wcs} and applied
during tessellation of Arc, Circle, and Line so they render correctly on
tilted planes in 3D DXF files.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>