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Author Topic: Quick question on scale  (Read 5005 times)

MetaUser555

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Quick question on scale
« on: July 07, 2015, 11:21:53 PM »
Hi,
I sometimes get a very small mesh from an agisoft scan.
Is there a way, in agisoft, to scale the mesh up.
I've already got processes to do this outside of agi but i just wanted to know if i'm missing a trick inside of agisoft itself.
Thanks for your help.

bigben

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Re: Quick question on scale
« Reply #1 on: July 08, 2015, 10:08:39 AM »
If you have the pro version you can add control points and enter the distances between them.  If it's the standard version then you'll need to do the scaling externally.

James

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Re: Quick question on scale
« Reply #2 on: July 08, 2015, 04:18:00 PM »
Just an observation here that may be relevant!

I did some tests shooting a concrete core sample at different angular intervals, and found that that the tighter the angular increments were, and therefore greater number of images, the larger the model was reconstructed in photoscan.

See image attached below. Largest cylinder was shot with 38 equally spaced images (180k sparse points), middle one had 19 images (60k sparse points), and smallest one had 13 images (20k sparse points).

However, without having looked into it any further (except that I know it did this on 2 separate but similar projects) i can't say that it is a direct result of number of images, angular separation of images or number of sparse points or what, but there is always the possibility of 'confirmation bias' at work http://www.nytimes.com/interactive/2015/07/03/upshot/a-quick-puzzle-to-test-your-problem-solving.html

MetaUser555

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Re: Quick question on scale
« Reply #3 on: July 08, 2015, 05:54:55 PM »
thanks for the replies.
Thanks bigben, I do have the pro version.
I'm entering the markers after the scan has been built. There is no difference to the exported mesh. Is the markers process needed to be done on the photos before any processing takes place, this is not really good for my automated workflow.
I tried adding markers to the mesh, setting  a distance and exporting - I believe this is what you recommended?
i exported the original mesh, one set at 1m and one at 100m, all were identical when loaded into my 3d program.
Is there something i'm missing here?

Thanks James, great observation! I've also seen the same results as you with the amounts of pics. I have 31 photos in my current scan which is giving me the resolution I need. I can't take any more as this will add time to processing that I can't afford so i'm looking for a specific solution in agi or i'll have to do the scaling externally.

thanks all.

James

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Re: Quick question on scale
« Reply #4 on: July 08, 2015, 06:02:19 PM »
Did you hit the 'update' button in the reference pane after adding your scale bar distance?

MetaUser555

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Re: Quick question on scale
« Reply #5 on: July 08, 2015, 06:12:06 PM »
that did it - i hadn't used the ref pane before so I missed that one [facepalm!]
that is all perfect now thanks!