id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
28	Assertion failed gfxcore.cc line 2232	Duncan Collis	Olly Betts	"On clicking 'show passage tubes' for the attached 3d file I get the following error message (which, incidentally, I can't copy + paste, which is unhelpful)

Microsoft Visual C++ Runtime Library

Assertion failed!

Program: C:\Program Files\Survex\aven.exe
File: gfxcore.cc
Line: 2232

Expression: z >=0.0"	defect	closed	minor		aven	1.2.1	duplicate	aven tubes assertion gfxcore