View point clouds created with Agisoft Photoscan

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AxelH
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Joined: Tue Nov 14, 2017 3:55 pm

View point clouds created with Agisoft Photoscan

Postby AxelH » Tue Nov 14, 2017 4:03 pm

Hei!

I have a question regarding point clouds created in Agisoft photoscan. I have problems with displaying/viewing/anIysing my 3D point cloud in CloudCompare. Other outputs such as DEMs and ortophotos that I have created are georeferenced and displayed correctly when using a GIS software. But when adding the point cloud to CC, the box dimensions are very very small and the cloud is seen only as a line i 3D space. I have tried both ASCII, LAS and e57.

What am I missing or what might be the problem?


Cheers,

Axel

daniel
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Re: View point clouds created with Agisoft Photoscan

Postby daniel » Tue Nov 14, 2017 4:17 pm

This looks like a scale issue: one dimension might not have the same units as the others?

CloudCompare reads the coordinates as they are stored in the file, and it doesn't handle such strange cases (especially since the information is generally not stored in the file).

Can you maybe send me a sample file to cloudcompare [at] danielgm.net? (the smallest one ;)
Daniel, CloudCompare admin

daniel
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Re: View point clouds created with Agisoft Photoscan

Postby daniel » Tue Nov 14, 2017 5:58 pm

Thanks for the file.

I confirm that there's a relative scale of 100.000 of the Z coordinate compared to the X and Y ones! I guess this comes from a setting in Agisoft?

You can counter-scale the cloud with the 'Edit > Multiply / scale' tool of CloudCompare (and apply a scale of 100.000 on X and Y only ;).

However, especially with the ASCII file where you only have 6 digits for the coordinates, you'll lose a lot of precision. There's probably a way to avoid that at export time in Agisoft?
Daniel, CloudCompare admin

AxelH
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Joined: Tue Nov 14, 2017 3:55 pm

Re: View point clouds created with Agisoft Photoscan

Postby AxelH » Tue Nov 14, 2017 6:04 pm

Okey, great. Thank you!

I'll try this and get back to you.

Thank you!!

AxelH
Posts: 6
Joined: Tue Nov 14, 2017 3:55 pm

Re: View point clouds created with Agisoft Photoscan

Postby AxelH » Tue Nov 14, 2017 6:33 pm

Hei, again.

So that worked but the cloud is only displayed as a 2D object in 3D view, any clues why?

When displaying my LAS files in e.g. ArcScene, that I get the 3D model without any distortions.

With regards to the coordinates, yes I need to check that in Agisoft, thanks.

Regards/Axel

daniel
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Location: Grenoble, France
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Re: View point clouds created with Agisoft Photoscan

Postby daniel » Tue Nov 14, 2017 6:51 pm

Not sure to understand what you mean by '2D' object. Did you apply the scale the right way?

Here are my parameters:
cc_rescale_parameters.JPG
cc_rescale_parameters.JPG (24.4 KiB) Viewed 93 times


And here is the result:
cc_rescaled_cloud.JPG
cc_rescaled_cloud.JPG (60.81 KiB) Viewed 93 times


However I strongly advise you to find the solution on Agisoft's side, otherwise you'll lose a lot of precision by working this way ;)
Daniel, CloudCompare admin

AxelH
Posts: 6
Joined: Tue Nov 14, 2017 3:55 pm

Re: View point clouds created with Agisoft Photoscan

Postby AxelH » Tue Nov 14, 2017 6:57 pm

Okey! I'll try again, I probably made somekind of mistake.

Yeah, going to check Agisoft, but tomorrow);

Thanks for the help, appreciate it!

/Axel

deepminder
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Re: View point clouds created with Agisoft Photoscan

Postby deepminder » Tue Nov 14, 2017 9:30 pm

Hi Axel,

Can you check the coordinate system in Photoscan export properties? If you have WGS-84, then your X and Y coordinates will be very small regarding to the Z (because you have longitude and latitude in degrees and not X and Y).
Point clouds should be in Cartesian coordinate system and not in Spherical coordinates. You can transform coordinates in Photoscan to any UTM projection, for example, and everything will be fine.

Best regards,
Denys.

AxelH
Posts: 6
Joined: Tue Nov 14, 2017 3:55 pm

Re: View point clouds created with Agisoft Photoscan

Postby AxelH » Tue Nov 14, 2017 9:35 pm

Yes, my cloud is in WGS 84. Perfect, I will try something more suitable then.

Thanks!


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