<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I am trying to draw the elliptic paraboloid z=4x^2+y^2 and have it enclosed in a box.<div>However, I want to cut the paraboloid at height z=4, which means I must draw it using surfaceparametree rather than \psssurface or other automatic graphing macros (all of which,</div><div>as far as I can tell, have domain necessarily specified as a rectangle in x and y, rather than an ellipse). </div><div>If I try to use \psSolid[object=parallelepiped, then the lines either overwrite or are overwritten by the surface (depending on the order in which I draw surface and box). However, axesboxed inside the drawing seems to yield nothing:</div><div>************************************************</div><div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\begin{pspicture*}(-3,-1.5)(3,5.5)</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\psset{unit=0.35}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\psset{lightsrc=40 50 50, viewpoint=18 65 30 rtp2xyz}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>\psSolid[object=parallelepiped,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>a=3,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>b=5,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>c=4.5</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>](-1.5,-2.5,0)</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\defFunction{Fpara}(r,t)%</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>{r t cos mul}%</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>{2 r t sin mul mul}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>{4 r dup mul mul}</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\psSolid[object=surfaceparametree,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>base=0 1 0 360,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>ngrid=32 32,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>grid,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>fillcolor=lightgray,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>incolor=blue!10,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>function=Fpara,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>axesboxed, Zmin=0, Zmax=4.5,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>]</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\axesIIID[showOrigin=false](0,0,3.45)(2,2,4.7)</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>\psSolid[object=parallelepiped,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>a=3,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>b=5,</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>c=4.5</div><div>%<span class="Apple-tab-span" style="white-space:pre"> </span>](-1.5,-2.5,0)</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>\end{pspicture*}</div><div>******************************************************************</div><div>shows no box at all.</div><div><br></div><div>Is there a way to enclose a surface defined parametrically in a box, but with appropriate hiding</div><div>of lines?</div><div>
<p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font-size: 12px; "><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-size: 12px; "><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-size: 12px; "><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-size: 12px; "><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; font-size: 12px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font-size: 12px; "><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-size: 12px; "><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-size: 12px; "><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-size: 12px; "><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><span class="Apple-style-span" style="font-size: 12px; "><a href="http://www.tufts.edu/~znitecki/">http://www.tufts.edu/~znitecki/</a></span>
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