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tickbox var: $explodeflag -- rip edge above $stressthresh
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default: 0 (FALSE)

The "explode" tickbox (F3 panel, bottom) toggles
whether to rip an edge between vertices if the
stress exceeds $stressthresh.

Adjust $stressthresh by 10% using the "FAT" and
"THIN" buttons (F3 panel, bottom right).

Stress is typically generated by ticking "expand"
($expandflag).  One an edge has ripped, a
stress-concentrating fracture will propagate to
neighboring edges.

Only affects shrink().  For a usage example, see
$CSURF_DIR/lib/tcl/explodemovie.tcl
