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Author Topic: 1,000+ Photo Project Workflow  (Read 4581 times)

dtmcnamara

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1,000+ Photo Project Workflow
« on: February 27, 2015, 06:45:30 PM »
I have seen a few people on here talk about extremely large dataset they have worked with on projects, upwards of 1,000+ photos, and was wondering what the normal workflow was for a project this big? I would guess something like this would be processes in different chunks with multiple overlapping pictures in each chunk. Im just a little lost when it comes to stitching everything together. I know with scanners like the Faro x130 you can use Scene to stitch everything together, but with the scans from Agisoft whats the best way to merge everything back into one large file?

stihl

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Re: 1,000+ Photo Project Workflow
« Reply #1 on: February 27, 2015, 09:34:26 PM »
Kinda depends what kind of images you're talking about.

Aerial photogrammetry or closed ranged photogrammetry?

I just finished up four facades of an old building, total of 3500 images. I just split the project into four facades and processed them seperately. Since I do not yet need a 3D model I haven't gone through to merging the facades together.

As for aerial photogrammetry - I've processed projects up to 80k images. Simply split up the images in reasonable chunks of 3-4k images which I let it run on medium dense quality. Takes 1-2 nights on my workstations. I use four workstations simultaneously which I do this with. This means 1 to 2 weeks of fulltime processing.

I make sure the chunks overlap with at least two flightlines. One from one chunk and one from another. This gives me an overlapping area of about 50 meters wide which is more than enough to feather chunks so they merge nicely. I merge the DEM's and Ortho's together in a dedicated GIS program such as GlobalMapper.

Do you have any specific questions I can answer?

dtmcnamara

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Re: 1,000+ Photo Project Workflow
« Reply #2 on: February 27, 2015, 09:49:22 PM »
My problem seems to start when trying to merge everyting together, im doing high detail scans of tunnels/walls/caves. Im trying to find the best way to export the mesh chunks and then merge them back together into one large model. I have tried a few different software, but when files get upwards of 50GB each with color and textures I get lots of crashes.

stihl

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Re: 1,000+ Photo Project Workflow
« Reply #3 on: February 27, 2015, 09:52:54 PM »
How many polygons does the mesh have? I assume millions.

Is it possible for your project to decimate the mesh to a lower amount of polygons so it's easier to work with?

If not, because you'll lose important geometry of the tunnels then I'd say it's best to leave the project in chunks instead.

dtmcnamara

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Re: 1,000+ Photo Project Workflow
« Reply #4 on: February 27, 2015, 10:01:57 PM »
Im working on this right now, testing different resolutions to see when I start to loose detail that is needed. The only drawback is that most of my scans will be .25-.5 miles long, so even with lower resolution I will still have massive files at the end of the day. Stitching scans 1-3 generally work great. I can then do scans 4-6, 7-9, 10-12 etc....then when I try to stitch then new bulk scan 1 to scan 2, I error out.

Does anyone have a software recommendation to use for stitching massive datasets together?

bigben

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Re: 1,000+ Photo Project Workflow
« Reply #5 on: February 27, 2015, 11:31:35 PM »
That is partly going to depend on your final requirements. What is the end use of the model? Measurement, static render, CG animation, interactive model? What are the requirements and limitations of this end use? Do you really need a single model or will multiple aligned sections work?  If you could stitch the entire model together would the next stage be able to cope with a large model?

stihl

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Re: 1,000+ Photo Project Workflow
« Reply #6 on: February 27, 2015, 11:54:08 PM »
Bigben makes an excellent point by saying what the next step is with one large model.

Does the end user have the computer power to use/view such a model if you are having trouble merging it in the first place.

dtmcnamara

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Re: 1,000+ Photo Project Workflow
« Reply #7 on: February 28, 2015, 03:30:10 AM »
I hope my rig can handle it. Current setup is

2011-V3 E5-2620V3
128GB DDR4 2133
Samsung 850 PRO Application Drive
Samsung 850 EVO Data drives
2 GTX-780

The end result is sort of CG animation, its similar to accident reconstruction. I use to take Faro scans in revit and recreated everything in there then animate in maya or blender. This was time consuming and since I dont own a Faro scanner I only could use it when it was availible. I would like to be able to take dense clouds or meshes and use them in the animations. Not only would this save me lots of time drawing everything out in revit, but it would also allow me to capture sites whenever I want.

I could use smaller datasets, but if it was possible to do everything in one set it would make for a quicker workflow.

I just got a demo of Geomagic and will try this out later this evening, once this current process is finished. I hope to have good news.

igor73

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Re: 1,000+ Photo Project Workflow
« Reply #8 on: March 01, 2015, 02:24:58 AM »
Have you tried Zbrush?  The new 4R7 is 64 bit and can handle massive models. Zbrush´s decimation master will also do a great job decimating the mesh but still keeping a lot of detail.  Probably better than any other decimation tool.  Merging the models in Zbrush you will lose the UV though and you will have an interesting task retopo a huge mesh like that to make a new UV. 

What i would do first  is try to align everything in one chunk.  With 128gb you can easily do this on high setting.  For dense cloud   1000 images you should also be able to handle on medium setting using a single chunk with 128GB.  I have 64GB and i can do around 2000  36 mpix inages on medium dense cloud.  For mesh you may have to divide up in chunks but you can probably handle around 1500 images if you processed on medium dense cloud.  . Make some overlap so camera based align will work and copy cameras on borders to the other chunks.  Hope that makes sense.

 The resulting merged model will not get welded points unfortunatley. This may not be a concern to you though.   Dynamesh in Zbrush will sort that out though but you will have to follow a pretty complicated workflow to get it all done with new UV´s.  If you plan to edit the texture you will need a new UV though.  The Agisoft generated one is tiled and impossible to edit. 

Edit.;  Reading your question  ton again i realize you want to merge un aligned chunks. Zbrush is probably not the best choise for that as you would have to align them by hand


« Last Edit: March 02, 2015, 03:12:22 PM by igor73 »

bigben

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Re: 1,000+ Photo Project Workflow
« Reply #9 on: March 01, 2015, 07:08:13 AM »
Then it will partly depend on your animation software and what it can handle.  I use Terragen for my visualisations as do Aerometrex who deal with much larger models than I do. https://www.youtube.com/user/Aerometrex  Tiling the output of a large point cloud  or aligned chunks should be OK for this type of  application. You shouldn't need to merge them as each section should retain its local coordinates.
« Last Edit: March 01, 2015, 07:25:29 AM by bigben »

dtmcnamara

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Re: 1,000+ Photo Project Workflow
« Reply #10 on: March 02, 2015, 03:26:07 PM »
Thanks, Ill try this out. I have a 3,000 photo project processing right now in 6 different chunks. I hope to have some sucess with one fo these software packages.

On a side note, I tried Geomagic and its great....but one thing I did find is that it does not scale before it aligns, or at least I could not get it to. So if different chunks are different scales it will not work. You have to scale evertyhing before trying to align unlink with other software packages where you can align and scale at the same time, then verify your scale at the end when everything is stitched together.

bigben

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Re: 1,000+ Photo Project Workflow
« Reply #11 on: March 17, 2015, 04:55:49 AM »
It's possible that Geomagic works the same as Meshlab, in that scaling the point cloud is off by default for aligning, but I'd expect it would have the abilaity to scale point clouds during alignment.

barrubba

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Re: 1,000+ Photo Project Workflow
« Reply #12 on: August 16, 2017, 04:35:21 PM »
I need an urgent help!
I've 1500 photos (phantom 4pro) of a church interior, top, floor and all facade.
It's a 3d cg animation job, so no need of target or centimetric precision. But texture must be high quality because of I'll do rendering!
I've a ws with fx 8350, 32gb and gtx 1060, plus a render node I7 6700 and 16gb.
I've to work with 1 chunk? Maybe I can half image resolution?