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Thank you for your quick reply, that helps a lot!

I shouldn't have problems with the true vertical distance since everything is aligned along Z. Also, I don't need extreme precision, it's just a rough representation of how the object looks like. We're automatizing a manual inspection and I'd like ...

Hello,

I took a picture of a flat-ish object from the top and I would like to fit it over the surface of the object's mesh model. I transformed the image in a cloud of points, one line for each pixel in the format x, y, z, r, g, b and I placed it over the mesh. Z is obviously constant because the ...

If your cloud is an ASCII file you can easily do that with a VBScript

The following is an example of a script that reads all the *.asc files in a directory and creates a copy of the cloud skipping all the "NaN" lines, which are not supported by CloudCompare (the ShapeDrive 3D scanner outputs "NaN ...

Ok, I can see more information now... I just have to figure out what to do with it! :)

Full explanation of what I'm doing:

1) load scanned cloud of a distorted plane
2) fit a plane to the cloud
3) orient the cloud so that the plane is orthogonal to Z
4) fit a 2.5D quadric to the reoriented cloud
5) save the vertices of the quadric to a cloud named "vertices.txt"

run the following ...

Can you test the latest beta version?

I'm on it! ;)

So far:

2.6.1 : [09:31:42] [doActionFitQuadric] Quadric equation: z = 0.191049 + 3.54679e-05 * x + 0.00128381 * y + -0.00411162 * x^2 + 0.00332104 * x.y + -0.000473885 * y^2

2.6.2.beta: [09:31:28] [doActionFitQuadric] Quadric equation: z = 0 ...

Thank you so much (I'm going crazy trying to convert the formula!!)

And thanks for CloudCompare, it's an amazing piece of software. Here at work we use 3D software products worth thousands of euros but we always install CC too because in many occasions it's just better and simpler ;)

I have the latest windows binaries

I'm really curious about finding out whether changing the coordinates of the formula would make an improvement.

My hope is that by using the output formula as it is I am reconstructing the "wrong" part of the surface, and when I try to superimpose it to my cloud ...

Then the Z should be good. I bet this is all about the gravity center?

It's like you said, the output formula doesn't reproduce the actual points of the fitted quadric surface

I am now comparing the saved output cloud produced by "Fit 2.5D quadric" with a cloud that I reproduced by calculating ...

- the axes may be changed [...]
- and the coordinates (and equation) are expressed relatively to the center of gravity of the input cloud

Well this explains why simply subtracting the calculated z(x,y) from the z-coordinate of each point in the cloud wreaks havoc (especially the second point)

I ...