Don't do numeric surface intersections if an exact curve has been copied. We don't want 2 overlapping but different sets of PWLs.

phkahler · phkahler · commit 8a3e5b4d56b6 · 2020-10-29T14:02:57.000-04:00
diff --git a/src/srf/surfinter.cpp b/src/srf/surfinter.cpp
@@ -331,6 +331,7 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
                 sext = this;
                 shext = agnstA;
             }
+            bool foundExact = false;
             SCurve *sc;
             for(sc = shext->curve.First(); sc; sc = shext->curve.NextAfter(sc)) {
                 if(sc->source == SCurve::Source::INTERSECTION) continue;
@@ -341,8 +342,14 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
                 if(splane->ContainsPlaneCurve(sc)) {
                     SBezier bezier = sc->exact;
                     AddExactIntersectionCurve(&bezier, b, agnstA, agnstB, into);
+                    foundExact = true;
                 }
             }
+            // if we found at lest one of these we don't want to do the numerical
+            // intersection as well. Sometimes it will also find the same curve but
+            // with different PWLs and the polygon will fail to assemble.
+            if(foundExact)
+                return;
         }
 
         // Try intersecting the surfaces numerically, by a marching algorithm.

Original file line number	Diff line number	Diff line change
`@@ -331,6 +331,7 @@ void SSurface::IntersectAgainst(SSurface b, SShell agnstA, SShell *agnstB,`
`331`	`331`	`sext = this;`
`332`	`332`	`shext = agnstA;`
`333`	`333`	`}`
	`334`	`+ bool foundExact = false;`
`334`	`335`	`SCurve *sc;`
`335`	`336`	`for(sc = shext->curve.First(); sc; sc = shext->curve.NextAfter(sc)) {`
`336`	`337`	`if(sc->source == SCurve::Source::INTERSECTION) continue;`
`@@ -341,8 +342,14 @@ void SSurface::IntersectAgainst(SSurface b, SShell agnstA, SShell *agnstB,`
`341`	`342`	`if(splane->ContainsPlaneCurve(sc)) {`
`342`	`343`	`SBezier bezier = sc->exact;`
`343`	`344`	`AddExactIntersectionCurve(&bezier, b, agnstA, agnstB, into);`
	`345`	`+ foundExact = true;`
`344`	`346`	`}`
`345`	`347`	`}`
	`348`	`+ // if we found at lest one of these we don't want to do the numerical`
	`349`	`+ // intersection as well. Sometimes it will also find the same curve but`
	`350`	`+ // with different PWLs and the polygon will fail to assemble.`
	`351`	`+ if(foundExact)`
	`352`	`+ return;`
`346`	`353`	`}`
`347`	`354`
`348`	`355`	`// Try intersecting the surfaces numerically, by a marching algorithm.`