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convert xyz sonar scan in stl

Posted: Fri Jun 12, 2020 1:04 pm
by JensKK
Hello everybody,

My Name is Jens, i am new in this segment but i hope my engineering skills and your expertise helps me to find a solution.

i have a underwater sonar scan of a tube ending in the river.
I am trying to convert this xyz sonar scan pointcloud into a stl model for 3D printing.

Cloudcompare breaks down if i try to compute normals at the point of 96%.
I thinks ist not a Problem with the size of the Cloud, i cut a segment out to the halve size, same Problem.
What is my mistake there?

Thank you!
Cloudcompare.png
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Re: convert xyz sonar scan in stl

Posted: Sat Jun 13, 2020 4:32 pm
by daniel
What do you mean by " breaks down"? Is it crashing or does it seem frozen?

Can you use the 'Tools > Other > Remove duplicate poins' and see if some points are removed and if yes, if it helps? Some clouds sometimes have a lot of points at the same position which can have bad effects on the octree-driven computations.

Re: convert xyz sonar scan in stl

Posted: Sun Jun 14, 2020 8:17 pm
by JensKK
Hello,
yes thanks that was the solution.
Now it works.
I created my first 3D mesh with the recon Plugin.
It is a bit raw, but i will Play a bit with the Settings.
Thanks!

Re: convert xyz sonar scan in stl

Posted: Sun Jun 14, 2020 10:00 pm
by daniel
I see that you didn't remove the parts of the mesh with low density (the bubbles, etc.). Was it intentional?

Re: convert xyz sonar scan in stl

Posted: Mon Jun 15, 2020 8:57 pm
by JensKK
How do i do this?

Is this the reason because the surface is so bad…
It Looks like the some points are swollen up.
In Pointcloud the Surface of the model was much more detailed…

Re: convert xyz sonar scan in stl

Posted: Tue Jun 16, 2020 12:41 pm
by daniel
See https://www.cloudcompare.org/doc/wiki/i ... n_(plugin) (and especially the section titled "Using the output density").

The dialog tries to explain you that as well, but it's easy to miss that.

And the Poisson Reconstruction algorithm will always try to produce a closed surface, even with big holes, bad normals, etc. Therefore it can produce strange bubbly things to achieve that.

Re: convert xyz sonar scan in stl

Posted: Tue Jun 16, 2020 4:35 pm
by JensKK
Thanks, i tryed it and now it Looks much better.
Enough for the first Prototyp print.