<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Hello,<BR> <BR>I have a question regarding volume rendering with gpu based volume ray casting and . <BR><BR>When I use the GPURenderDemo example (provided with VTK 5.6.1),the rendering gives an assertion failure<BR> <BR>Assertion '"check: positive_low_bounds" && lowBounds[2]>= 0.0"'<BR> <BR>And when implementing volume rendering with the vtkFixedPointVolumeRayCastMapper there 's no volume rendred (no crash just a black window)<BR> <BR>I looked at the original images and it seems that spacing between slices is 0 <BR> <BR>spacing[0] == 0.679688<BR>spacing[1] == 0.679688<BR>spacing[2] == 0<BR> <BR> <BR>Please let me know if you have run into this .<BR><BR>How can I avoid this problem ?<BR> <BR>Thank you in advance<BR><BR></td></tr></table><br>