<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Ah! Your reply inadvertently told me about another mistake I was making: I read the "lt" as "It" (with the font I use, it is hard to tell the two apart---I should probably switch). It also explained the last "dup". <div>Thanks!<br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; "><br class="Apple-interchange-newline">Zbigniew Nitecki</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Department of Mathematics</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Tufts University</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Medford, MA 02155</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">telephones:</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Office<span class="Apple-converted-space"><span class="Apple-converted-tab"> <span class="Apple-converted-space"> </span></span></span>(617)627-3843</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Dept.<span class="Apple-converted-space"><span class="Apple-converted-tab"> <span class="Apple-converted-space"> </span></span></span>(617)627-3234</font></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Dept. fax<span class="Apple-converted-space"><span class="Apple-converted-tab"> <span class="Apple-converted-space"> </span></span></span>(617)627-3966</font></p><a href="http://www.tufts.edu/~znitecki/">http://www.tufts.edu/~znitecki/</a></span>
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<br><div><div>On Aug 21, 2010, at 2:41, Herbert Voss wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Am 20.08.2010 22:48, schrieb Zbigniew Nitecki:<br><blockquote type="cite">I would like to do it so the top of the surface is horizontal---since the cross-section is not a circle,<br></blockquote><blockquote type="cite">r=1 will give me height 4 along the x-axis but height 1 along the y-axis. Is there an equivalent to<br></blockquote><blockquote type="cite">It -5 It{pop -5}fi which cuts the surface off if the value is above a given one, instead of below it (in my case, 4)? This problem was why I initially used surfaceparametree with a variant of polar coordinates.<br></blockquote><br><br>\documentclass{article}<br>\usepackage{pst-solides3d}<br>\pagestyle{empty}<br>\begin{document}<br><br> \begin{pspicture}(-4,-5)(6,8)<br> \psset{lightsrc=viewpoint,viewpoint=50 60 30 rtp2xyz,Decran=60}<br> \psSurface[ngrid=.2 .2,incolor=yellow,linewidth=0.5\pslinewidth,<br> r = 2,fillcolor=cyan,<br> axesboxed,<br> Zmin=0,Zmax=4](-1,-2)(1,2){<br> 4 x dup mul mul y dup mul add<br> dup 4 gt {pop 4} if }<br> \end{pspicture}<br><br>\end{document}<br><br>dup => copy the z value<br>z > 4 => compare it with 4<br>pop 4 => delete the z value and put 4 on the stack<br><br>Herbert<br>_______________________________________________<br>PSTricks mailing list<br><a href="mailto:PSTricks@tug.org">PSTricks@tug.org</a><br>http://tug.org/mailman/listinfo/pstricks<br>archive: http://www.tug.org/pipermail/pstricks/<br></div></blockquote></div><br></div></body></html>