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Messages - matt07lx

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General / GCPs vs Scale Bars
« on: April 18, 2023, 10:08:29 PM »
I was wondering if somebody could explain the relationship of ground control points and scale bars within a model. If you use both, are scale bars considered to be "more accurate" in scaling, and hence prioritized? In my typical use, GCPs are set with a total station, in which error typically is around a cm, whereas I can use target based scale bars with errors lower than a mm. Do the scale bars simply as a control to check the GCP errors, or do they improve the accuracy of the model scale?

General / Characterize Model Accuracy in Real World Units?
« on: April 06, 2023, 07:35:06 PM »
Hi All - I was wondering if anyone can suggest the best method for characterizing a model's accuracy in terms of real units (e.g. meters)? Thinking through this problem, it seems to be that using a calibrated scale bar (with targets) might offer the best reading of overall model accuracy since the target centers can be located with high precision. GCPs set with a total station or GPS will likely have errors larger than a cm or more, so these can't be used to understand model accuracy below this level. I don't know how well the scale bar error characterizes the accuracy across the whole model though, since they will only be a small part of the overall model.

I've wondered if the reprojection RMS error (pixels) can somehow can be converted to real world units? If I were to take the average RMS reprojection pixel error and multiply it by the ground resolution, would that give an approximation of the average error in real units?

Python and Java API / Re: Batch processing of numerous PSZ files
« on: August 07, 2019, 07:45:07 PM »
Hi Alexey,

Thank you so much for your very quick response! This works perfectly, and I was able to adapt it for my needs. Can I also ask if you plan to add a Python function to enable select dense cloud points by shape? I would like to batch process a number of projects with a single shape to produce models with the exact same extents.

Python and Java API / Re: Batch processing of numerous PSZ files
« on: August 07, 2019, 05:12:48 PM »
Sorry for restarting an old post, but is there any way to change this script to include psz files in all subdirectories, too? I have all of my projects organized in this way and want to batch process a number of different psz files in multiple subdirectories. I tried to make this work, but with my limited knowledge of Python I couldn't make it work.

Thanks so much!

Bug Reports / Re: Sketchfab Upload: "OpenSSL Library Not Found"
« on: July 22, 2019, 08:11:26 PM »
Yes, I've tried 1.0.2.s, which is the only 1.0.x version currently available:

Bug Reports / Sketchfab Upload: "OpenSSL Library Not Found"
« on: July 22, 2019, 07:41:10 PM »
I get the following message when I try to upload to Sketchfab directly from Metashape: "OpenSSL Library Not Found: Please Install OpenSSL 1.0 for Data". I've installed several versions of OpenSSL (64 and 32 bit), restarted Metashape and my computer, and nothing seems to work. Any ideas? I've never had this issue before.


Thanks so much for sharing the latest version of the script. When I run it now I get the following error: "UnboundLocalError: local variable 'a' referenced before assignment". Do you have any thoughts as to why I am getting this error?

Can anyone confirm if this works in 1.5? I've tried running it and it just freezes upon trying to build the orthomosaic.

General / Palaeo3D Scale Bars?
« on: June 06, 2019, 11:58:44 PM »
Just curious if anyone has purchased scale bars from Palaeo3D ( They are much more affordable than the ones made by Cultural Heritage Imaging (, but I'm wondering how durable they are. If anyone out there has a set, would you say they are appropriate for archaeological fieldwork? Will they break easily since they are foam?

General / Identify Coordinates of Object Center?
« on: January 24, 2019, 06:58:19 PM »
Is there currently a way to identify the coordinates (in a projected coordinate system) of a 3D model's center point? Alternatively, is there a way to create a target or point on the center of the model that will help me get these coordinates? Perhaps a python script can be written to do this? I need the coordinates of the center in order to correctly locate the model when imported to ArcGIS (there are known issues with locating georeferenced models in ArcGIS. I think this may help me develop a workflow to get around these issues).


General / Re: Model Location shift after import to ArcScene
« on: September 18, 2017, 12:43:06 AM »
Just in case anyone else ever finds this, I thought I would share the that I was able to figure this out. It had to do with the length of the UTM coordinates. I found this old threat that describes how to trim the number of digits using the "Shift" parameters in the Export Model dialogue:

After shortening the UTM coordinates, I'm now able to import the COLLADA models into ArcScene and they are aligned perfectly. They also display the texture correctly after the first step! I don't have to use the awkward process where you have to do "Replace With Model" from a model in Local Coordinates, as there are numerous tutorials out there explaining. The problem is the length of the UTM coordinates.

General / Model Location shift after import to ArcScene [Solved]
« on: September 16, 2017, 06:29:01 AM »
This is more of a GIS question than Photoscan, I suppose, but I figure someone here might know the answer. I created a series of models in Photoscan of archaeological layers that are all georeferenced using the same markers shot with a total station one time. Therefore I am able to stack them in several programs (CloudCompare and Photoscan, too, by appending the various models into the same project), and they align perfectly since they use the exact same markers with the same exact UTM coordinates. However, when I import the Collada files into ArcScene as multipatch layers, each model ends up slightly shifted (perhaps a few centimeters). Nothing aligns perfectly, even when if I import the UTM coordinates of the markers as a shapefile.

The odd thing is that I've even checked the orthomosaic files from the same models, and they align in ArcMap perfectly, and the UTM markers are precisely located on the targets, etc. What's the difference between orthomosaics in ArcMap and multipatch files in ArcScene that I'm missing? Is it something to do with the UTM coordinates getting rounded down or something in the conversion from Collada to multipatch?

Bug Reports / Re: Photoscan freezes when opening photos in tab
« on: August 08, 2017, 10:20:49 PM »
I actually just performed a clean install of Windows 10 build 1703 on my laptop, so I don't think it is related to the update. I had noticed the problem first after updating, but had to do a clean install today because of other issues affecting my system.

Bug Reports / Re: Photoscan freezes when opening photos in tab
« on: August 08, 2017, 09:44:18 PM »

I'm experiencing the same exact problem after updating my OS to Windows 10 build 1703. I've tried the newest driver for my GTX 960M (384.94), but that hasn't worked. I'll try downgrading to 382.33 like the previous user.

General / Re: Orientation of a wall for orthophoto
« on: June 26, 2017, 05:54:22 PM »
If you already have a coordinate reference system in place in your model (from a total station, for example), there is another method you can use, detailed in this thread:

This works perfectly for me to make orthomosaics of walls, archaeological profiles, etc.

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