<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I want to draw (in one pspicture) the level surfaces of f(x,y,z)=x^2<span class="Apple-style-span" style="font-size: 12px; ">+y^2</span><span class="Apple-style-span" style="font-size: 12px; ">-z^2 </span><div>for the values -1,0, and 1. </div><div><br></div><div>My attempt to do this with \parametricplotThreeD is not so successful: either I have</div><div>a collection of lines (and difficulty hiding some) or if I use enough plotpoints, the </div><div>inside stuff is totally wiped out. So I'm trying to see if I can do it more easily in</div><div>pst-solides3d.</div><div><br></div><div>The cone for 0 is easy. I tried to understand from</div><div>the example at the end of section 6.6.4, p. 90 in the (English) documentation for</div><div>pst-solides-3d how to draw a hyperboloid of one sheet in this system, but</div><div>I need someone to parse for me the function definitions embedded in it.</div><div><br></div><div>Here is the code in the example:</div><div><br></div><div><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">\</span></font><span style="color: #4658e4"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">begin</span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">{</span></font><span style="color: #ca0000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">pspicture</span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">*}(-5,-5)(3,5) \psSolid[object=new,fillcolor=red!50,incolor=yellow,</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; color: rgb(0, 132, 103); "><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">hollow, a=10, </span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">%% nb d’etages </span></font><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">b=20, </span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">%% diviseur de 360, nb de meridiens </span></font><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">h=8, </span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">%% hauteur </span></font><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">action=draw**,sommets=</span></font></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">/z0 h neg 2 div def a-10{</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">/k exch def 01b1 sub {</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">/i exch def /r z0 h a div k mul add dup mul 4 div 1 add sqrt def 360 b idiv i mul cos r mul 360 b idiv i mul sin r mul z0 h a div k mul add</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">} for } for, faces={</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">0 1 a 1 sub { /k exch def k b mul 1 add 1 k 1 add b mul 1 sub { /i exch def [i i 1 sub b i add 1 sub b i add]</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">} for [k b mul k 1 add b mul 1 sub k 2 add b mul 1 sub k 1</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; "><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">add b mul] }for</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; color: rgb(202, 0, 0); "><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">}] \</span></font></span><span style="color: #4658e4"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">end</span></font></span><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">{</span></font></span><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">pspicture</span></font><span style="color: #000000"><font class="Apple-style-span" size="4"><span class="Apple-style-span" style="font-size: 14px;">*}</span></font></span></div></blockquote><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; ">I am having trouble understanding the structure of lines 3-8.</span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; ">Can anyone explain it for me? I have (limited) experience with postscript, but none with jps.</span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; ">Zbigniew Nitecki</span><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; ">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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