Using 12.1.1.0 on MacOS BigSur I observe quitting Mathematica kernels when evaluating RegionIntersections on two regions that apparently only touch.
Example for Regions that cause the Kernel to quit without throwing error messages:
RegionIntersection[
Polyhedron[{{-14.481838045552937`, -3.8913713702921195`,
13.743481930417099`}, {-13.387327710535084`, -4.686579676023987`,
14.579613424294676`}, {-13.592704266151834`, -3.145108820945274`,
14.801904645288225`}, {-12.786161768700419`, -4.476126018218702`,
13.92490718079964`}, {-12.982315767496441`, -3.0038758320024415`,
14.137216281827229`}, {-13.831522463803132`, -3.716627016121334`,
13.126322670747593`}}, {{1, 2, 3}, {5, 4, 6}, {4, 5, 3, 2}, {3, 5,
6, 1}, {4, 2, 1, 6}}],
Cuboid[{-13.2`, -6.`, 14.375`}, {-10.8`, -3.5999999999999996`,
15.625`}]]
These are the regions:
When I only slightly change the coordinates to get regions that either overlap or do not overlap at all, I get the intersection polyhedron or the empty region indicator instead.
These are the regions that do overlap
RegionIntersection[
Polyhedron[{{-14.481838045552937`, -3.8913713702921195`,
13.743481930417099`}, {-13.387327710535084`, -4.686579676023987`,
14.579613424294676`}, {-13.592704266151834`, -3.145108820945274`,
14.801904645288225`}, {-12.786161768700419`, -4.476126018218702`,
13.92490718079964`}, {-12.982315767496441`, -3.0038758320024415`,
14.137216281827229`}, {-13.831522463803132`, -3.716627016121334`,
13.126322670747593`}}, {{1, 2, 3}, {5, 4, 6}, {4, 5, 3, 2}, {3, 5,
6, 1}, {4, 2, 1, 6}}],
Cuboid[{-13.25`, -6.`, 14.375`}, {-10.75`, -3.5999999999999996`,
15.625`}]]
with the corresponding output:
and the corresponding 3D graphics:
These are the regions that do not overlap
RegionIntersection[
Polyhedron[{{-14.481838045552937`, -3.8913713702921195`,
13.743481930417099`}, {-13.387327710535084`, -4.686579676023987`,
14.579613424294676`}, {-13.592704266151834`, -3.145108820945274`,
14.801904645288225`}, {-12.786161768700419`, -4.476126018218702`,
13.92490718079964`}, {-12.982315767496441`, -3.0038758320024415`,
14.137216281827229`}, {-13.831522463803132`, -3.716627016121334`,
13.126322670747593`}}, {{1, 2, 3}, {5, 4, 6}, {4, 5, 3, 2}, {3, 5,
6, 1}, {4, 2, 1, 6}}],
Cuboid[{-13.15`, -6.`, 14.375`}, {-10.85`, -3.5999999999999996`,
15.625`}]]
The output here is EmptyRegion, and the corresponding 3D graphics is:
Input
Mathematica code insteadOutput
? $\endgroup$Rationalize
the numeric values prior to calculation. $\endgroup$