--- Operating System, Graphics card ---

Ubuntu Linux 12.04/x86_64, nVidia GTX 560, nVidia driver 319.92

--- Blender version with error, and version that worked ---

I am using 2.69 RC2 (2.69.0 r60761). I did not use other version and do not know whether bug exists in other versions.

Blender was downloaded from official site.

Filename: blender-2.69-RC2-linux-glibc211-x86_64.tar.bz2
Filesize: 76175975
sha1sum: 904c02c4ad04cd6192e3a9a27815478ba8768bd5

--- Short description of error ---

Doing a boolean union on 2 very simple planes causes Blender to hang forever. I have tried making planes 'touch' each other, intersect each other (partially and fully), and Union bool would hang every time.

Running it in gdb and interrupting it with CTRL+C (or CTLR+|) after it hangs produces this:

(gdb) where
#0 0x00000000016e27a0 in double carve::rescale::calc_delta<double>(double, double) ()
#1 0x00000000016e0209 in BOP_performBooleanOperation(EnumBoolOpType, BSP_CSGMesh**, CSG_FaceIteratorDescriptor, CSG_VertexIteratorDescriptor, CSG_FaceIteratorDescriptor, CSG_VertexIteratorDescriptor) ()
#2 0x00000000016d7523 in CSG_PerformBooleanOperation ()
#3 0x0000000001196274 in NewBooleanDerivedMesh ()
#4 0x0000000001187279 in ?? ()
#5 0x00000000015c116b in ?? ()
#6 0x00000000015c218a in ?? ()
#7 0x00000000014d5edb in BKE_object_handle_update_ex ()
#8 0x00000000014c2b77 in ?? ()
#9 0x00000000014c2dfb in BKE_scene_update_tagged ()
#10 0x0000000000f9e474 in wm_event_do_notifiers ()
#11 0x0000000000f8bbc0 in WM_main ()
#12 0x0000000000f86c79 in main ()

So I guess it's possibly stuck in some infinite loop.

If planes are extruded, Union works as expected.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---

Create 2 planes, scale down second one, move it so that it 'touches' 1st plane and is snapped to same grid line, then choose bigger plane, add Boolean modifier, select Union and choose 2nd plane object. Blender will hang. Same will happen if 2nd plane is moved around and intersects 1st plane.

I have observed same behavior when using CPU or CUDA as computing device, changing that setting didn't make any difference.

Blender file is attached. Load it, then choose "Plane.001" in the Object menu (in Modifer submenu on the right hand side).

Granted, I am a real beginner and have no idea what I am doing, so maybe using Union in this way is not something that should be done. Regardless, Blender shouldn't hang when newbie does something stupid ;)