Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - AFB

Pages: [1]
Bug Reports / Re: UTM Model Export Failing
« on: April 13, 2018, 11:10:41 AM »
Hi All,

I thought that I would revive this post, as I am having the same issue as Erich with the export model function of Agisoft. There doesn't appear to be a satisfactory work around for this as of April 2018. I am exporting 3D models (both .dae and .wrl, same problem with both) into an ArcScene (10.5) environment, using the same coordinate system - WGS 84 UTM zone 35S.

This issue has been around for some time, and a few years ago a team from the DARK lab at LUND university posted a work around for the model geometry issue in ArcScene - export a WGS model from PS, as well as a model in LOCAL coordinates - import first the WGS model into ArcScene (to a file geodatabase), edit the model and select it using the edit placement tool, then replace the model with the LOCAL version. This fixes the geometry problem most of the time, however all the models that I have used this on are now out by a few cms. One could 'move' the model using the edit - move function, however this is a clunky process, crashes often and is not really satisfactory when we're dealing with many models.

Now as I understand it (from reading many posts on these forums that deal with similar problems), the issue isnt so much with PS as with other software storing the coordinates in a different format (float vs double?).  A work around for this problem has been to use the SHIFT functionality in PS when exporting the model. I have had success with removing the first three digits from the GCPs (eg from X: 363999.999 to 999.999). However, this is not exactly satisfactory when we our aim is to integrate the models with a large volume of data collected in UTM, say for artefacts that have been piece provenanced using a total station (as is the case for both Erich and I). Unless all the spatial data is appended in this way, the shift function doesnt appear to help with this issue. From what I can see, PS adds 6 decimal places to the UTM coordinates (eg. X: 363999.999000), and I am wondering if this might be where the problem lies? Is it possible to use the shift function to remove the last three decimals and would this work?

One aspect of this problem that I am finding hard to understand is the export of LAS files (dense clouds). I routinely export a LAS and a 3D model for all models - the LAS files import into ArcScene in the correct position, without any issues. It doesnt appear to me that anything has changed in the coordinate system or the way that PS exports the coordinates, and it doesnt seem to have any issues with ArcScene. This is also the case for orthomosaics and DEMs (they work fine in my experience. So it appears the problem is isolated to 3D models.

Is there any way that the PS team could create a function for exporting to other software to change the format that the coordinate system is stored in and hopefully solve this issue?

If anyone knows of any workarounds that avoid appending the coordinate system please post them! I cannot presently see a useful solution, unless we are happy to tolerate inaccurate models in the correct coordinate system. Perhaps a transformation from a projected to a geographic coordinate system would do the trick? This would, however, be a time costly solution if we are dealing with many models..


Pages: [1]