Root cause: base _w2s mapped world-Z directly to screen-Y (which
increases downward), placing the keel at the TOP of every viewer.
BodyPlanViewer:
- Override _w2s/_s2w/_fit_to_view to invert Y axis (keel now at bottom)
- Fix section drawing: remove keel-appended B-spline closure that
distorted the curve; close section with a straight lineTo(0,0) instead
ProfileViewer:
- Same Y-inversion overrides as BodyPlanViewer
- Add _compute_buttock_pts() helper (interpolates Z at constant Y_b
across all stations) and draw 3 buttock lines (B/4, B/2, 3B/4)
as smooth curves in the profile view
Buttocks, stations and waterlines now appear in their correct views:
Body Plan → station cross-section curves, keel at bottom
Profile → buttock curves (vertical long. sections), keel at bottom
Plan View → waterline contours (unchanged)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
alro65
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