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Author Topic: Cull/Cut by Low-Density tool.  (Read 21704 times)

Infinite

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Cull/Cut by Low-Density tool.
« on: February 25, 2012, 01:09:27 AM »
Hi Alexey,
 
I’ve been trying to think of an elegant way to easily solve masking and cutting with the more volumetric type captures.
 
It dawned on me looking at some High and Ultra builds today, maybe there is a solution inside Agisoft before export and after build.



Notice how dense the “important” areas are and how sparse the useless “garbage” areas are. The important areas are so well formed it seems like it would be an ideal way to cull the garbage data based on the low-density of the mesh? what do you think? does that sound like a feasible thing to implement?
 
This would make aligning and handling 360 data so much easier, by having to hand very quick culling tools.
 
Interested to hear your thoughts on yet another topic : )
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RHenriques

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Re: Cull/Cut by Low-Density tool.
« Reply #1 on: February 25, 2012, 02:42:14 AM »
I subscribe this request!! While using Photoscan for terrain modelling, the same problem occurs. The useless geometry is always the most sparse one, with faces well bigger than the useful ones. A tool for cutting geometry based in the face's dimension would be very welcome.

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Infinite

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Re: Cull/Cut by Low-Density tool.
« Reply #2 on: February 25, 2012, 02:05:39 PM »
Cool to hear another user like this idea : ) You can see on the geometry build how it kind of fades in from REALLY dense to sparse. Even if we got some kind of polygon group addition to the sparse geometry area, or black and white grey scale clip map built when the texture phase is created as an alpha, it would help. I'm sure there must be a way to calculate a smooth fall off between the two, and find a way to keep the desirable geometry, rather than rely on masking and cutting.
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akemono

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Re: Cull/Cut by Low-Density tool.
« Reply #3 on: March 01, 2012, 03:17:57 PM »
What you could try is the following:
  • Roughly select the area you don't want, don't have to be much just a little part/bit
  • Now use the page up and page down buttons to control the size of the selection(you'll see the selection grow or shrink)
  • And press delete when you have the desired area that you want te get rid off

Hope that makes your process a bit easier

best,
Mike

Infinite

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Re: Cull/Cut by Low-Density tool.
« Reply #4 on: March 03, 2012, 06:29:37 PM »
Hi Mike, thanks yeah I have done that previously in ZBrush using masking tools to paint the areas I want to remove. Which is a bit more precise but even then can lead to user error, removing useful areas, or even miss bad areas.

Like your suggestion it's time consuming. Being able to automate the process with a one button click can save hours in a day if you have dozens of captures to process.

The idea being here that the software can analyse the mesh data to find areas that are low density and accurately (not by eye or by hand) remove them.

Does that make sense? It would make the process more accurate and very quick.
Lee

What you could try is the following:
  • Roughly select the area you don't want, don't have to be much just a little part/bit
  • Now use the page up and page down buttons to control the size of the selection(you'll see the selection grow or shrink)
  • And press delete when you have the desired area that you want te get rid off

Hope that makes your process a bit easier

best,
Mike
« Last Edit: March 03, 2012, 06:36:45 PM by Infinite »
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Infinite

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Re: Cull/Cut by Low-Density tool.
« Reply #5 on: March 05, 2012, 03:16:41 PM »
It seems that Meshlab http://meshlab.sourceforge.net/ is able to delete Garbage polygons by their edge size or Area, using "select polys by edge length"



thanks to Carolina Larsson, Paolo Cignoni, Lehel Seres for their suggestions.
« Last Edit: March 05, 2012, 03:18:18 PM by Infinite »
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Alexey Pasumansky

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Re: Cull/Cut by Low-Density tool.
« Reply #6 on: March 05, 2012, 03:57:20 PM »
Hello,

If you mean only a selection tool (like connected components selection for example) that selects faces based on their sizes, I think we could add such a tool to one of the upcoming updates, but deleting these faces will lead to the saw edged model (and it will be more visible in case of Height Field models).
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Alexey Pasumansky,
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RHenriques

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Re: Cull/Cut by Low-Density tool.
« Reply #7 on: March 05, 2012, 04:47:48 PM »
Alexey, it would be a tool that could work in a very similar way as the one in meshlab, that Infinite is refering to. I tested that tool with good results but, unfortunately, I can not use it because meshlab destroys the georenferenced information produced by photoscan.
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Infinite

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Re: Cull/Cut by Low-Density tool.
« Reply #8 on: March 05, 2012, 04:51:30 PM »
Hello,

If you mean only a selection tool (like connected components selection for example) that selects faces based on their sizes, I think we could add such a tool to one of the upcoming updates, but deleting these faces will lead to the saw edged model (and it will be more visible in case of Height Field models).

I think it could possibly be quite useful, select by edge size similar to meshlab, which has a default setting like 0.01 +/- so you can choose, or similar to your % slider? The saw edge is no problem really, it is almost the same effect than if you process as Sharp. It's just Smooth seems to create a more useful mesh on the internal important areas, apart from the unwanted garbage areas which are good to remove if the user chooses to.
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mala

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Re: Cull/Cut by Low-Density tool.
« Reply #9 on: March 05, 2012, 06:20:35 PM »
+1 from me.

Having this selection option would be very handy..perhaps also, once it had selected the size polys you require you could also have the option to grow/shrink that selection by very small increments ?

fpbv

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Re: Cull/Cut by Low-Density tool.
« Reply #10 on: March 08, 2012, 11:12:05 PM »
Very interesting.
Actually, quite handy if possible.
If don?t loose the georeference it will be nice too!!

AJ

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Re: Cull/Cut by Low-Density tool.
« Reply #11 on: March 14, 2012, 03:23:46 PM »
+1 here too!

Alexey Pasumansky

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Re: Cull/Cut by Low-Density tool.
« Reply #12 on: September 05, 2012, 06:13:45 PM »
Hello all,

Gradual selection criterion by polygon size was added in PhotoScan 0.9.0 build 1556.
Best regards,
Alexey Pasumansky,
Agisoft LLC

Infinite

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Re: Cull/Cut by Low-Density tool.
« Reply #13 on: September 05, 2012, 10:06:03 PM »
Hello all,

Gradual selection criterion by polygon size was added in PhotoScan 0.9.0 build 1556.

Wow! very cool, thank you  :)
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RHenriques

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Re: Cull/Cut by Low-Density tool.
« Reply #14 on: September 07, 2012, 02:10:05 AM »
This tool is just perfect!! Works even better than in Meshlab.
Congratulations Agisoft for this small and hidden tool but a great achievement for user's productivity.

Cheers