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Newbie

3D Plots

Can anybody explain to me in more clear terms the usage of the 3D Surface Plot function it MathCad 8? (Although it is the same problem I had in 6...)

What I want to do: Graph a 3D Function (eg. x^2+y^2)
Problem: Manual and help files are a bit cryptic, do not cover my question, or are too terse for me; I can only get the first 1/4 of values (non-negative values of X and Y) to plot correctly. The other 6 octants in 3-Space are not plotted, nor is of the function within it.

I've seen some ways of doing it, so I know it can be done. The problem is I have no clue how to set the X and Y domains of the function so that I have the equivalent of the 2D plot domain X:=-10, -9.9 . . . 10. And of course, a similar value for the domain of Y.

If at all possible, I would like to have a form where I can use the domains in the same fashion as in a 2D plot, and plug those values into the solution matrix.

Just how it works is a bit unclear to me... I gather that it fills out a matrix of Z for the corresponding X and Y values, and that the plots I've seen that *should* be through the origin are really shifted so that the X and Y values are always positive - so they fit in the matrix. And of course then the axes are completely wrong, but those can be shut off.

I have found a .mcd that is (sortof) a help, that being the param.mcd found in the mathcad 8 knowledge base; I'll attach it if you want to take a gander. My problem is that this method, while (somewhat) easier to understand, requires a LOT more typing.

3 REPLIES 3

3D Plots

I threw together a Mathcad 8 file which I hope helps.

3D Plots

Michael Thackston took the words out of my mouth (almost) when replying to your message in Feature Suggestions. Mathcad 2000 has a great new 3D quickplot feature. It certainly saves time. You don't need to bother defining matrices anymore (but it's backward compatible if you like doing it the old-fashioned way).

3D Plots

This one uses a method I use by standard. It graphs TRUE parametric plots. It is fairly simple and straightforward and does not use a single matrix.
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