I have created a test file with only two spaces and a total of 5 surfaces. They both look exactly the same but one (e7) crashes while the other (e8) does not crash. e8 was made by taking e7 and moving one of the spaces a few times and then back to the original location. This file does not directly supper from the SketchUp intersect but that makes odd diagonal lines, but maybe there is a similar core issue? I have emailed the file to @macumber but I'll find a place on the network for them soon.@lgentile, I'll add this to Pivotal now that we have more to go on.
Here is an initial summery of the diff's of the two files. There are changes in all 5 surfaces, which is a bit odd, as two of them (Surface 1 and Surface 3) were in a space that was not touched. but in comments below I can narrow it down to a single vertex value. Also if you go to the crashing file (v7) and remove any of the 5 surfaces, intersect won't crash it anymore.
Surface 35, vertex 4
E7 -4.8641002032, -2.84479960791214, 2.79136546036137e-030; !- X,Y,Z Vertex 4 {m}
E8 -4.8641002032, -2.84479960791214, 7.81582328901191e-029; !- X,Y,Z Vertex 4 {m}
Surface 54 vertex 3 (this is a common point to surface 35)
E7 -4.8641002032, -2.84479960791214, 6.69927710486735e-029, !- X,Y,Z Vertex 3 {m}
E8 -4.8641002032, -2.84479960791214, 7.81582328901191e-029, !- X,Y,Z Vertex 3 {m}
Surface 17 (all 4 vertices changed, and in x,y,&z, vs. just in z)
E7 1.3721262813875e-011, -3.35280167186981, 5.3359104714532, !- X,Y,Z Vertex 1 {m}
E7 -4.86410020320009, -3.35280036549766, 5.33589202837834, !- X,Y,Z Vertex 2 {m}
E7 -4.86410020319988, -3.35279934681557, 7.30763488926745e-014, !- X,Y,Z Vertex 3 {m}
E7 -1.20135833253303e-013, -3.3528006531842, -7.09398344747063e-014; !- X,Y,Z Vertex 4 {m}
E8 1.38071556551538e-011, -3.35280135205875, 5.33591047145323, !- X,Y,Z Vertex 1 {m}
E8 -4.86410020319999, -3.35280000000003, 5.33589202837841, !- X,Y,Z Vertex 2 {m}
E8 -4.86410020319998, -3.3527997123132, 3.29872092895969e-015, !- X,Y,Z Vertex 3 {m}
E8 -2.06028674725995e-013, -3.35280097299526, -1.04612436956894e-013; !- X,Y,Z Vertex 4 {m}
Surface 1
E7 -1.46757023317472e-037, -1.15505827125162e-014, 3.74294931277106e-019, !- X,Y,Z Vertex 1 {m}
E7 1.46757023163683e-037, -6.753225, -1.87147465255285e-018, !- X,Y,Z Vertex 2 {m}
E7 -5.72769980280216, -6.75322500000003, -4.11724424069883e-018, !- X,Y,Z Vertex 3 {m}
E7 -5.7276997968, -7.94102561485488e-015, -1.87147465451548e-018; !- X,Y,Z Vertex 4 {m}
E8 5.7276997968, -7.94102561485488e-015, -1.87147465451548e-018, !- X,Y,Z Vertex 1 {m}
E8 1.46757023317472e-037, -1.15505827125162e-014, 3.74294931277106e-019, !- X,Y,Z Vertex 2 {m}
E8 1.46757023163683e-037, -6.753225, -1.87147465255285e-018, !- X,Y,Z Vertex 3 {m}
E8 -5.72769980280216, -6.75322500000003, -4.11724424069883e-018; !- X,Y,Z Vertex 4 {m}
Surface 3
E7 8.59135517801374e-028, -6.75322499999995, 3.57665764490041, !- X,Y,Z Vertex 1 {m}
E7 -5.72769982218217, -6.7532250000001, 3.50528987642782, !- X,Y,Z Vertex 2 {m}
E7 -5.72769981273667, -6.75322500000012, -3.08872326694553e-017, !- X,Y,Z Vertex 3 {m}
E7 -8.20050777011538e-028, -6.75322499999996, -1.87147465268921e-018; !- X,Y,Z Vertex 4 {m}
E8 5.45000032332442e-028, -6.75322499999995, 3.57665764490041, !- X,Y,Z Vertex 1 {m}
E8 -5.72769982218217, -6.7532250000001, 3.50528987642782, !- X,Y,Z Vertex 2 {m}
E8 -5.72769980280216, -6.75322500000003, -4.11724424069883e-018, !- X,Y,Z Vertex 3 {m}
E8 1.46757023163683e-037, -6.753225, -1.87147465255285e-018; !- X,Y,Z Vertex 4 {m}