original prisim fault:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb4136b70 (LWP 29262)]
0x081771b1 in pov::Prism::Normal (this=0x83c9080, Result=0xb41340a0, Inter=0xb4134080, Thread=0x838dbf8)
    at shape/prism.cpp:758
758			Entry = Spline->Entry[Inter->i2];

additional fault modes (converted ply2pov mesh and ovus):

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb4afdb70 (LWP 29560)]
0x081c3acb in pov::Trace::ComputeSubsurfaceScattering (this=0x8390950, Finish=0x8397148, layer_pigment_colour=..., 
    out=..., Eye=..., Layer_Normal=..., Final_Colour=..., Attenuation=1, ticket=...) at render/trace.cpp:3837
3837				if (IsSameSSLTObject(unscatteredIn.Object, out.Object))