Agisoft Metashape

Agisoft Metashape => Bug Reports => Topic started by: gEEvEE on April 29, 2012, 05:25:31 PM

Title: Export Model
Post by: gEEvEE on April 29, 2012, 05:25:31 PM
Hi PS users,

I have a 3D model of a Roman gate that I would like to export. The camera positions are known to 2 cm accurate by using D-GPS. The idea is that I have all the vertices of the model in the WGS84 or UTM-ETRS89 coordinate reference system. However, I am unable to do so. I tried almost all possible options (binary coding on and off, different formats, different coordinate reference systems) but the export creates:
* just lines, or
* very blocky models. Even stetting the precision to 20 does not seem to help.

Does anyone have a solution for this? Cheers,

Geert
Title: Re: Export Model
Post by: Kjellis85 on April 29, 2012, 05:38:32 PM
I am not sure if this is a fix for that problem, but I have experienced something similar. If I have georeferenced a model in WGS 1984 33N, then I must choose only WGS 1984 when export the model. As I sai, not sure it is the same problem, but you could try this.
Title: Re: Export Model
Post by: Alexey Pasumansky on April 29, 2012, 05:53:29 PM
Hello Geert,

Could you please provide the project file to us?

Also there could be a problem with non-projected geographic coordinate systems when x and y are in degrees. Due to the different scaling of the coordinates you can get highly deformed faces of the model. Please check that you are exporting model in projected coordinate system.
Title: Re: Export Model
Post by: gEEvEE on April 29, 2012, 10:04:09 PM
Hi Alexey,

indeed, geographical coordinates just export a line. However, when I use projected coordinates (UTM 33N, ETRS89 or UTM33N WGS84), the appearance is extremely blocky. (see attachment)

I will put a similar (smaller) project file online, which has exactly the same error.

Regards, Geert
Title: Re: Export Model
Post by: Kjellis85 on April 30, 2012, 12:11:07 AM
Are you opening the exported file in meshlab? I have heard from the guys behind meshlab that they have a real big problem with viewing models that have coordinatesystems bigger than three digits before comma. There are no real work-arounds, or so I have been told. The only thing you can do is to go into the file and move the decimal separator a few steps to the left.

You could also try the meshlab forum http://sourceforge.net/projects/meshlab/forums/forum/499532 (http://sourceforge.net/projects/meshlab/forums/forum/499532)
Title: Re: Export Model
Post by: gEEvEE on April 30, 2012, 12:29:42 AM
OK, I will try but I do not really have any expectations, as I opened up the file in both Geomagic and Rapidform and these $$$$$ programs showed the same blocky appearance.
Title: Re: Export Model
Post by: Wishgranter on April 30, 2012, 12:03:11 PM
Can upload on dropbox the scene file ? *.psz romat ? PM me with link.....

i have here Geomagic but the Polyworks suite too. Can test few things.....
Title: Re: Export Model
Post by: gEEvEE on April 30, 2012, 12:15:48 PM
Well, not really. Images are for publication and we do not like to share them at this stage. As said, I have Geomagic, Rapidform, RiScan Pro, Meshlab, VRMesh, Cinema 4D. I tried all possible things but nothing really worked (in none of these packages).
Title: Re: Export Model
Post by: Wishgranter on April 30, 2012, 01:26:32 PM
hmm. OK understand.....

But is here a option that you export just unreferenced model and then in other app add the coordinates ?
And can set the comma to 3decimal numbers ? make it difference ?

Can send just a 25k mesh eventuely ? just for tests ???
Title: Re: Export Model
Post by: Alexey Pasumansky on May 01, 2012, 12:06:03 PM
Hello,

Seem like most of the 3D editors store coordinates in float type (and not in double) and the although the "Precision" parameter value is set to a dozen of digits they are not used when imported in the external editor.

So maybe exporting the model in local coordinates with KML file (WGS84 coordinate system) could be an alternative.
Or it is also possible to use "Shift" parameters in export model dialog.
Title: Re: Export Model
Post by: sflo on June 03, 2016, 01:08:13 PM

Hello,

this problem has never been solved, not even in the actual version (2.4) ? I experienced the same issue with meshlab, 3D studio max, maya, etc... every single software I tried gives blocky models totally ugly.
Problem is that for some operations the projected model is absolutely needed and the local coordinates model is totally useless. So how is it possible to proceed 4 years after this issue was firstly discussed ?

Cordially,
Title: Re: Export Model
Post by: Alexey Pasumansky on June 03, 2016, 01:43:49 PM
Hello sflo,

I'm not sure it is PhotoScan problem actually, when the external applications store the coordinate information in float format, thus limiting the number of significant digits to eight.
If you open the mesh models exported in geographic coordinates in any text editor you'll see that PhotoScan saves the coordinate information correctly.

However, if you have the experience with properly working models in UTM coordinates with the mentioned packages (like MeshLab) maybe you can share the working example of such model and the required workflow steps on the model import to those application?
Title: Re: Export Model
Post by: sflo on June 03, 2016, 02:41:13 PM
Hello Allexey,

thank you for this fast answer.
I usually  work on 3gb models and 10 gb psz files, so it is difficult to share one of them.
I use Lambert93 2154 coordinates system but also notes same issues with WGS and all others.
Of course, I have no doubt that Photoscan stores the coordinates information properly and I am aware that the problem is the importation in other software. But why don't you simply propose an option to export for "meshlab and co" reducing the number of significant digits ?

Nevertheless, do you have any procedure to reduce manually the accuracy to 8 significant digits when exporting a model? Besides it is very bad for me to proceed working from 1 cm models accuracy to 10 cm model accuracy, I don't see any other solution.

Thank you again.
Title: Re: Export Model
Post by: Alexey Pasumansky on June 03, 2016, 02:43:41 PM
Hello sflo,

You can use Offset fields in the Export Model dialog to subtract high numbers from the coordinates, like millions and thousands of meters. Would it work as a workaround for you?
Title: Re: Export Model
Post by: sflo on June 03, 2016, 03:00:44 PM
Well, I can't see any "Offset fields" option in the Export Model dialog  :-\
Title: Re: Export Model
Post by: Alexey Pasumansky on June 03, 2016, 03:21:54 PM
Hello sflo,

In the interface they are named as Shift, sorry for the confusion.
Title: Re: Export Model
Post by: Dukytony on June 10, 2016, 09:58:41 PM
I got the same problem. Could you please explain how the shift parameter really works? what to enter in the fields?

I got coordinates like this format :

xxxxxx.xxxxxx
yyyyyy.yyyyyy
zzzzzz.zzzzzz

Thanks a lot!
Title: Re: Export Model
Post by: Alexey Pasumansky on June 11, 2016, 10:34:21 PM
In Shift fields (in Export Model dialog) you can input huge values that will be subtracted from the model coordinates. For example, if you have X,Y coordinates like 12235833.171 and 727355.045, you can input 12230000 and 72000 in the corresponding fields, so the coordinates of the vertices for the exported model (in the example) would be 5833.171, 7355.045.
Title: Re: Export Model
Post by: Outis79 on July 29, 2016, 12:48:18 PM
Hi all,
I had to face the same problem. My model has planar coordinates (Monte Mario Italy1) and even using the shift tool in exporting model or pointcloud I get a blocky mesh with the real planar coordinates.
In order to solve the problem I've:
1)placed 3 points on the mesh (or you can use 3 GCPs you already have):
2)removed the first digits of their coordinates in order to have  only coordinates with 3 digits before the comma (1592401.561245 to 401,561245 for example)
3)switched all the other GCPs off
4)used the update tool in order to move my model to the new truncated coordinates
5)exported the model.

You might use 3 GCPs you already have as well
You need to pay attention to one thing:
whether you decide to truncate the digits in order to have 3 digits before comma you need to choose CGPs which are within a buffer of 999 meters along the longitude and latitude
More clearly the digits of the coordinates of the choosen points you want to truncate need to be the same, for example I can't choose a point with a long=1592401.xx and another  with a long=  1593401.xx, indeed truncating the first 4 digits I would have 401.xx for both. Same thing for the latitude and elevation.
I hope that can help.

Anybody can tell me if you got problem with the shift tool that would be a great tool but for me looks not to work. Anyway what's the base point used for the shift tool?
Thanks.
 
Title: Re: Export Model
Post by: Alexey Pasumansky on July 29, 2016, 12:50:17 PM
Hello outis79,

Can you post the values you are using for the Shift fields and coordinate of any reference point in the project?
Title: Re: Export Model
Post by: Outis79 on July 29, 2016, 04:07:34 PM
Hi Alexey,
thanks for the very quick reply.
The version I'm currently using is 1.2.5 build 2735.
The SRS of my project is Monte Mario Italy1.
In the attachment you can see the GCP's coordinates, the shift values I set, and the result in Meshlab with the Pick Point tool that shows the coordinates. In static mode the model looks good but when I move it gets trembling.
Am I making any mistake? Is there a problem with this particular SRS and should I use WGS84 UTM instead?

Can you tell me what's the base point of the shift transformation? Of the same area I have 2 different set of aerial photos taken in different periods and I would need to compare the 2 mesh model. So I would need to apply the shift on both based on the same base point.

Thanks again
   
Title: Re: Export Model
Post by: Alexey Pasumansky on July 29, 2016, 04:12:39 PM
Hello outis79,

I suggest to select the same coordinate system used for the chunk referencing in the Export Model dialog, then input values to be subtracted, so no need of negative values.

Now it looks like from the local coordinates (internal coordinates that might be close to zero) you are subtracting barge negative values - i.e. adding large values.
Title: Re: Export Model
Post by: Outis79 on July 30, 2016, 02:06:52 PM
Thank you Alexey,
using positive values It works. I thought I had to specify negative values.
So into the shift tool we have to write positive values: when we export the mesh (or the pointcloud) the values are substracted, when we import the mesh the values are added.
Thanks again for your help.