How can I plot a 3D displacement field from scattered data?

I am studying the deformation/distortion of a welded plate and I have a txt file with the displacement and coordinates of several points,

The data is obtained through an optical system and identifys points introduced in the plate.. I take two measurements one before welding as a reference and another after welding and the software stores coordinates and displacement of the several points detected in the plate in a txt file.

I wanted to do something similar to the attached file. I haven't started yet but I leave this question for some advice to know where to start.

Sincerely

Daniel Sousa

Answer 1

[Star Strider]

It looks like a surf plot. However you probably need scatteredInterpolant or its friends if you only have a few scattered values rather than a grid, or one of the gridded interpolation functions if your data are regularly-spaced on a grid to get the detailed surfaces in the attachment.

[Daniel Sousa]

Thank you for the reply. I haven't started yet but I think both functions will help a lot.

:D

[Star Strider]

My pleasure.

[Daniel Sousa]

I have managed to plot surfaces around my scattered data. But I still have some issues.

Hello,

The method of the distortion measurements is not ideal so the information I have is rotated in relation to all planes as you can see in the attached image. I wanted to put all the scattered data alligned in the X-Y plane.

I know that this sort of question have been asked and I have discovered the fucntion PCA but I still don't know how to use it in terms of Inputs and Outputs. Is there a easier way to do it?

Another thing the surf plot creates an extra surface on a place with no scattered data (Vertical lines in the red surface in the attached file). Is there a way to delete this part? See attached file.

Best regards,

Daniel

[Star Strider]

I’m not certain what you’re doing. I thought you had scattered data that you wanted to interpolate and create a fit to a gridded surface. If you want to use scatteredInterpolant to extrapolate your data to a specific grid beyond the data you have, choose an interpolation method (perhaps 'linear') and use the 'extrap' option.

I don’t know what you would be using PCA for.

[Daniel Sousa]

Maybe I was not clear..

the plot I have there that is what I want and thank you for that. But the data I have is not ideal because of the set up method..

What I want now is to rotate the plot or 'drag' the plot to the Plane XY.. As you can see the surfaces I have are in the space in obliquous position all I want is the surfaces to be horizontal or paralel to plane xy. (I.e. Blue plane co-planar or paralel to plane XY)

Best regards

Daniel

[Star Strider]

I’m still sort of lost.

One possibility (if I’m understanding you correctly — no promises there) is to use the rotate function.