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Jan 28, 2013
04:25 AM

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Jan 28, 2013
04:25 AM

3D-plot of a set of x,y,z coordinates ?

Hello !

Primary problem:

I have a set of x,y, and z coordinates in vector format, attached in file. How can I plot them in a 3D-graph ? My problem is analoge to a 2D-plot where I have x and y coordinates in vector format, which I have no problem to plot in a 2D-graph, see attached file.

Is this not possible in MathCad today ?

Secondary problem:

Is there no fix to the display problem of 3D-graphs in Windows 7 ? I have problems to display the 3D-graph at all. I have right clicked and unchecked the boarder function, which helps to display the 3D graph. However, as soon as I start scrolling in the work sheet the 3D graph disappears. It doesn't feel very satisfactory.

I would really appreciate your comments on this. Thanks in advance !

Rasmus

11 REPLIES 11

Jan 28, 2013
04:53 AM

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Jan 28, 2013
04:53 AM

Rasmus Friberg wrote:

Hello !

Primary problem:

I have a set of x,y, and z coordinates in vector format, attached in file. How can I plot them in a 3D-graph ? My problem is analoge to a 2D-plot where I have x and y coordinates in vector format, which I have no problem to plot in a 2D-graph, see attached file.

Is this not possible in MathCad today ?

Yes, but you have a lot of unnecessary zeros in your vectors - display one and scroll along to see (might be better to use the subvector function to extract elements from vec).

Rasmus Friberg wrote:

Secondary problem:

Is there no fix to the display problem of 3D-graphs in Windows 7 ? I have problems to display the 3D-graph at all. I have right clicked and unchecked the boarder function, which helps to display the 3D graph. However, as soon as I start scrolling in the work sheet the 3D graph disappears. It doesn't feel very satisfactory.

It isn't satisfactory; however, we've no choice but to live with it!

Alan

Jan 28, 2013
05:43 AM

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Jan 28, 2013
05:43 AM

Rasmus Friberg wrote:

Hello !

Primary problem:

I have a set of x,y, and z coordinates in vector format, attached in file. How can I plot them in a 3D-graph ? My problem is analoge to a 2D-plot where I have x and y coordinates in vector format, which I have no problem to plot in a 2D-graph, see attached file.

Is this not possible in MathCad today ?

As Alan say, yes it is possible but rather depends upon what you want to do. I've limited the data to the values prior to index 27 (the start of the zeros) and used the 3DPlot component's Data Points plot type to show that effectively have a space curve (straightish line in this case) rather than a surface. I've also plotted T on the secondary axis of your 2D plot ... it's saved in M15 (which should load in M14).

Secondary problem:

Is there no fix to the display problem of 3D-graphs in Windows 7 ? I have problems to display the 3D-graph at all. I have right clicked and unchecked the boarder function, which helps to display the 3D graph. However, as soon as I start scrolling in the work sheet the 3D graph disappears. It doesn't feel very satisfactory.

I think it's machine dependent. I'm running Windows 7 Ultimate (32-bit) on a Dell Dimension E521 with a Radion X1300 graphics card and have no problems (apart from some of the plot going black occasionally, which corrects itself when I click on the offending plot). I tend to run quite a few 3D plots at the same time.

Stuart

Jan 28, 2013
07:40 AM

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Jan 28, 2013
07:40 AM

Dear Stuart,

Thanks a lot for your response. It helped me and created a few more questions.

Apart from the unnecessary zeros in the original matrix, I realise that I was very close to the correct solution. The main problem was that I needed parantheses around the argument, that is the three vectors, for the 3D-plot. I noticed that you have used that.

Is the only function of that parantheses to inform the 3D-plot to use the elements of the vectors instead of the indices ? I haven't seen any instructions in the MathCad Help regarding the parantheses. That was very important to understand. Thanks again !

Another question that arised is: you used the function subvector. I haven't seen that before. I have M15, and when I try to use that function in my worksheet it says the function doesn't exist. However, your worksheet works perfect with the subvector function. I find it strange. I normally use the function submatrix, but it would be nice to use the subvector when I only have a vector.

cheers Rasmus

Jan 28, 2013
12:52 PM

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Jan 28, 2013
12:52 PM

Rasmus Friberg wrote:

Dear Stuart,

Thanks a lot for your response. It helped me and created a few more questions.

Apart from the unnecessary zeros in the original matrix, I realise that I was very close to the correct solution. The main problem was that I needed parantheses around the argument, that is the three vectors, for the 3D-plot. I noticed that you have used that.

Is the only function of that parantheses to inform the 3D-plot to use the elements of the vectors instead of the indices ? I haven't seen any instructions in the MathCad Help regarding the parantheses. That was very important to understand.

The 3D Plot Help and Quicksheets mention the use of parentheses to group the x, y and z components together to form a single entity.

Thanks again !

No worries, Rasmus.

Another question that arised is: you used the function subvector. I haven't seen that before. I have M15, and when I try to use that function in my worksheet it says the function doesn't exist. However, your worksheet works perfect with the subvector function. I find it strange. I normally use the function submatrix, but it would be nice to use the subvector when I only have a vector.

You won't find subvector in M15 (or any other version). You will find a closed Area near the top called "Utilities" which will contain the definition. The Area also includes a few other functions that I frequently find useful, particularly vec and seq. I've also got a refined version of submatrix that interprets negative bounds as being relative to the last row or column (as does subvector), which I also find quite useful. Another functions that I've redefined is matrix, which now allows vector and range arguments in place of the integer m and n - again, more useful as I rarely define functions with purely integer arguments; I have also defined an equivalent function 'vector' that works in a similar fashion to matrix.

Stuart

Jan 28, 2013
06:41 AM

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Jan 28, 2013
06:41 AM

If you need a steam enthalpy as function of p and T you can use a cloud function - see please the picture and the attach:

Jan 28, 2013
06:51 AM

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Jan 28, 2013
06:51 AM

Dear Valery,

Thank you very much for your response. Indeed, it is a steam enthalpy function I need. I will have a look at the one you have sent me and see how it works. I didn't know about the cloud functions. Are there functions for "everything" in the cloud ?

//Rasmus

Jan 28, 2013
09:21 AM

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Jan 28, 2013
09:21 AM

Rasmus Friberg wrote:

Dear Valery,

Thank you very much for your response. Indeed, it is a steam enthalpy function I need.

You welcome!

You can also use the WaterSteamPro - see www.wsp.ru

I didn't know about the cloud functions

See please http://twt.mpei.ac.ru/ochkov/WSPHB/Web-function-Power-Eng.pdf

Are there functions for "everything" in the cloud ?

I hope in future but now I have a lot of them for Power Engineering.

Jan 28, 2013
09:35 AM

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Jan 28, 2013
09:35 AM

Hi Valery,

Is your MathCad code for steam enthalpy calculations something you like to share ? I am about to code the equations found in the paper you have referred to. However, it would save me some time if you are willing to share your mathcad worksheet.

Thanks for you references.

Best Regards,

Rasmus

Jan 28, 2013
09:56 AM

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Jan 28, 2013
09:56 AM

No problem.

You can share this and same others my function.

Jan 28, 2013
10:29 AM

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Jan 28, 2013
10:29 AM

Valery,

Thanks for sharing your work. However, it is tremendously lot of work you have sent me.

Could you guide me to the steam enthalpy equations you have implemented in MathCad ?

Rasmus

PS. I can be reached on email

Jan 28, 2013
12:23 PM

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Jan 28, 2013
12:23 PM

Rasmus Friberg wrote:

Valery,

Thanks for sharing your work. However, it is tremendously lot of work you have sent me.

Could you guide me to the steam enthalpy equations you have implemented in MathCad ?

Rasmus

See please http://www.iapws.org/relguide/IF97-Rev.htm