From f9355bdc8f28eb5d7b5e6c059b1c970ce2763b6b Mon Sep 17 00:00:00 2001 From: Emily Boudreaux Date: Sat, 19 Sep 2026 14:03:31 -0400 Subject: [PATCH] Document curved slice conformity and refinement limits --- experiments/MODEL_SLICES.md | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/experiments/MODEL_SLICES.md b/experiments/MODEL_SLICES.md index d705323..44fcafa 100644 --- a/experiments/MODEL_SLICES.md +++ b/experiments/MODEL_SLICES.md @@ -86,6 +86,16 @@ projecting reference positions of the deformed cut would be a different curve. An exactly coplanar surface patch is reported as unsupported instead of being silently drawn as a unique intersection curve. +The tetrahedral subdivisions are conforming inside each parent hexahedron, +but their face diagonals are not made globally consistent across differently +oriented neighboring elements. Boundary faces are triangulated independently +as well. On a curved shared face, these choices can produce slightly different +chord approximations: small gaps or overlaps between neighboring element fills, +or a mismatch between the colored edge and the independently drawn outline. +Deterministic ownership of a coincident planar face does not remove this curved +interface approximation. These image artifacts must not be interpreted as +physical gaps, jumps in geometry or an additional density feature. + Curved cuts are displayed using straight triangles and boundary chords. Field colors are piecewise linear on those triangles, not exact values throughout their interiors. Root tolerances, maximum physical-plane residuals, sampled @@ -96,6 +106,15 @@ between subdivision vertices can be missed; compare subdivisions for image stability. This visualization does not certify pointwise positivity or exclude small unsampled features. +Before interpreting an actual FEM image, export the same saved state and plane +at two subdivision counts, for example 6 and 12 (or 4 and 8 for a first bounded +check). Compare the outlines, element-interface seams, sampled chord errors and +the visible density/enthalpy structure at the same axes and color ranges. The +pure geometry and plotting controls below do not test differently oriented +neighboring curved hexahedra and do not replace this export refinement check. +Globally consistent face triangulation would remove the diagonal mismatch; +it is not implemented in this bounded diagnostic. + ## Checks Every export runs pure geometric controls: unit-cube section area, integration