3d image reconstruction via XYZ coordinates

[Olataro]

Hi, I'm stuck for a while now so i guess it is time to get some help.

My project is based on the idea where there are a series of XYZ coordinates (2000++ of em) and using them, I am supposed to re create a 3D image. Question is, how do I accomplish this on LabView?

I searched around and I think I am supposed to use the 3D surface plot VI? I'm not really sure how to use it though, or sure if it is the correct VI to use. Please help!

[Olataro]

Is there anyone who is familiar with this?

[altenbach]

Is this related to your other question here?

Hi, I'm working on a similiar project here and was wondering if the surface graph could be used to build a 3D model based on a cloud of XYZ coordinates. Also, I'm a bit confused about the Z- axis array. Is it possible to explain this in a little more detail?

It is not clear at all what you have in mind and how the data is arranged. What is a 3D image? What is a "cloud of ploints"?

Can you show us a picture? Do you want a simple surface (exactly one Z value for each xy pair)? Do you want a parametric surface in space (e.g. a sphere or a donut, etc.? Do you want an isosurface given a 3D array of values?

Please explain exactly what kind of data you have and how the output is supposed to look like.

[Olataro]

Hi altenbach, thank you for your reply. In truth I'm kind of lost here and i cant seem to find much information on 3D modelling as the concept is pretty new to me. Thank you for clarifying what i need to add.

First of all, about the data. THe data is obtained from a cathether probe. So imagine a string, wrapped around a ball. Only the ball is totally covered by 1 layer of string throughout the surface, That should be how the data are arranged.

As for the image, my professor obtained such image using matlab; using the command "surface plot" if I'm not mistaken. I'm not really sure about the specific nature of the plot, but hopefully your better eye and experince can help me out.

And again, thank you for your reply.

[altenbach]

Do you have some sample data?

[Olataro]

Hmmm, sry for the delay. I'm still waiting for my lecturer's permission. Is there anything else you need to know?

[Olataro]

Sorry for the delay, my lecturer gave me the green light. This is the set of data. A number of them are in negative numbers. That....I'm not really sure if labview can handle that.

But for the decimal points, i was wondering if the VI cant process them, could i just convert them integers?

Eg: 12.34 when converted is 1234

IS this plausible or a bad idea?

[altenbach]

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@Olataro wrote:

Sorry for the delay, my lecturer gave me the green light. This is the set of data. A number of them are in negative numbers. That....I'm not really sure if labview can handle that.

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LabVIEW, like any other programming environment, has the capabilities to deal with fractional and negative data. Why do you think this is a problem?

If you don't get the expected result, it could have something to do with the way you read the data, with the datatype you select, and possibly with the localized decimal point setting (some parts of the world use the comma as decimal seperator instead of a period). Since you don't show us how you are reading the data, we cannot tell what you are doing wrong.

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@Olataro wrote:

IS this plausible or a bad idea?

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As said, the right way is to read the data correctly, so let's solve that first. Sorry, I don't have excel on my current computer, but it might be easier to save the data a plain text (tab delimited) using excel. This way it can be read much more directly by LabVIEW.

[Olataro]

Thank you for the quick reply. I was under the impression that certain VI's dont work well with decimal points, my bad (had a hard time with decimal points when i was programming alterra FPGAs).

Anyway sir, will you be able to view the data using excel? As the data is much neater that way. That said though, i've made 2 copies of the file in txt format. One was made by copying the data while the other was made by using excel to convert it to txt delimited.

I really appreciate the time taken to help me guide me with the program.

So here are my questions i hope you can help me with for now before i try my hand at the build

1) Looking at the image made(using matlab), will 3D surface plot be able to construct that type of model?

2) There are a few types of 3D construction VI's, so I'm not really sure which should I use
3) Why is "Z" data in the 3D surface plot a 2D array? How am I able to derive a 2D array from my 1D array of Z?

[Olataro]

OK, as per Altenbach's suggestion, i redid the input design with help from fellow forumers. In the end though, Gogineni's suggestion was simpler and much more efficient so i decided to use his design.

okay so basically I'm stucked in building the Z matrix for the 3D surface plot.  The 3D scatter looks good though, and seems to be quite similiar to the one generated from Matlab.

I wanted to try using 3D parametric surface VI but it demands X,Y and Z to be in a 2D matrix. Which I am unsure of how it actually works. I try reading the sample coding and also searching the internet but there doesnt seem to be much information on this.

Help please?