3D Scatter Plot - Single Point

[shie0041]

Here's a really stupid question. I've looked through the "Creating Amazing Images with Mathcad 14" book as well as the collaboratory and still can't find an answer, though.

How do I create a 3D scatter plot of a single point? If I pass in a vector (x, y, z) it plots three points: (0, 0, x), (1, 0, y), and (2, 0, z). This seems like an unusual default for a 3D plot.

What I really want to do is to plot three points and label them A, B, and C. I can plot the three points in a scatter plot by passing in vectors for (X,Y,Z), but since I will rotate the plot simply dragging text regions over it will not suffice. Since Mathcad doesn't allow simple annotation of plots (see Matlab's text(x,y,z,'string') function for instance), I figured I could plot the three points separately and assign them different colors.

(Now I'll vent a bit.)
If anybody at PTC is reading this: How do you get to version 14 of a maths/engineering tool where plotting is significant and still not have annotation capabilities? Would it be so hard to accept a vector where the first three terms are x,y,z coordinates and the fourth term is a string?

Any advice would be appreciated.

Thanks,
Eric

[RichardJ]

Type (X,Y,Z) in the placeholder, where X, Y, and Z are single element vectors, not scalars.

Richard

[TomGutman]

>>If I pass in a vector (x, y, z) it plots three points: (0, 0, x), (1, 0, y), and (2, 0, z). This seems like an unusual default for a 3D plot.<<

What you think is a vector of x, y, and z is seen by the plot routine as a matrix of z values, with the x and y values being implicitly the row and column indices. One of the unfortunate side effects of not having actual vectors in Mathcad and confounding the concept of vector with that of a one column matrix.
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� � � � Tom Gutman

[ptc-1368288]

"If anybody at PTC is reading this: How do you get to version 14 of a maths/engineering tool where plotting is significant and still not have annotation capabilities? Would it be so hard to accept a vector where the first three terms are x,y,z coordinates and the fourth term is a string?

Any advice would be appreciated".
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1. keep reading the collab,
2. read the qs examples.

Re-specify some plots attached ...

Plot a center.



jmG

[ptc-1368288]

... some plots got screwed.

jmG

[shie0041]

Thanks for the speedy replies everybody. I'd previously tried creating a 3x1 matrix where each element was a 1x1 matrix, but all that ended up doing was converting the matrix to be of size 4x2. I guess it didn't occur to me to try passing in three 1x1 matrices.

Thanks again.

-Eric

[TomGutman]

>>I'd previously tried creating a 3x1 matrix where each element was a 1x1 matrix<<

You can do that. But you cannot create nested matrices by using ctl-m on a placeholder within a matrix constructor. As you noticed, when used within a matrix constructor ctl-m acts as insert rows/cols rather than insert matrix. You can build the nested matrix by assigning matrices to matrix elements. Or you can create a nested matrix constructor by pasting matrix constructors into the placeholders of a matrix constructor.
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� � � � Tom Gutman