<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>Hello,</DIV>
<DIV>&nbsp;</DIV>
<DIV>I have a question regarding volume rendering with gpu based volume ray casting and . <BR></DIV>
<DIV>When I use &nbsp;the GPURenderDemo example (provided with VTK 5.6.1),the rendering gives an assertion failure</DIV>
<DIV>&nbsp;</DIV>
<DIV>Assertion '"check: positive_low_bounds" &amp;&amp; lowBounds[2]&gt;= 0.0"'</DIV>
<DIV>&nbsp;</DIV>
<DIV>And&nbsp;&nbsp;when implementing volume rendering with the vtkFixedPointVolumeRayCastMapper <SPAN id=result_box class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">there 's no volume rendred (no crash just a black window)</SPAN></SPAN></DIV>
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'"></SPAN></SPAN>&nbsp;</DIV>
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">I looked at the original images and it seems that spacing between<FONT style="BACKGROUND-COLOR: #ebeff9"> </FONT>slices is 0 </SPAN></SPAN></DIV>
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'"></SPAN></SPAN>&nbsp;</DIV>
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">spacing[0] == 0.679688</SPAN></SPAN></DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">spacing[1] == 0.679688</SPAN></SPAN></DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">
<DIV><SPAN class=short_text><SPAN style="BACKGROUND-COLOR: #fff" onmouseover="this.style.backgroundColor='#ebeff9'" title="Il n' y a pas" onmouseout="this.style.backgroundColor='#fff'">spacing[2] == 0</SPAN></SPAN></DIV></SPAN></SPAN></SPAN></SPAN>
<DIV>&nbsp;</DIV>
<DIV>&nbsp;</DIV>
<DIV>Please let me know if you have run into this .<BR><BR>How can I avoid this problem ?</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thank you in advance<BR></DIV></td></tr></table><br>