Re: Plot3D Problem with Nonreal Numbers

*To*: mathgroup at smc.vnet.net*Subject*: [mg20042] Re: Plot3D Problem with Nonreal Numbers*From*: "Allan Hayes" <hay at haystack.demon.co.uk>*Date*: Sat, 25 Sep 1999 18:46:07 -0400*References*: <7shqcb$1rn@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

JAM <jmac at tiac.net> wrote in message news:7shqcb$1rn at smc.vnet.net... > Greetings All! > I'm hoping you can help this struggling artist generate this 3D plot > destined for a calculus textbook. If the author had provided me with a > notebook file I wouldn't have to be bothering you, but he didn't. All I > have is a sketch of something that resembles two funnels joined at the > narrow end and this equation: > > x^2 - y^2 + z^2 = 4 > > I have solved for z and used the results in Plot3D but this generates an > error for the points that are not real numbers and only a portion of the > plot is drawn. > The question is, is there a way to make Mathematica ignore the solutions > that are not real? Or is there some other technique I should be using to > render this graphic. > Be gentle. Remember I'm an artist, not a mathematician. > Thanks in advance for any and all assistance. > --Jim > Jim, You might find the package << Graphics`ContourPlot3D` useful. Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565