Forum : Photosynth Lounge

Photogrammetric, Oblique Image Stitching, Pets Dressed in Clothes Photos… this is a place to chat and share stories with your fellow Photosynthers. Not all topics have to be about photography, this is a place to relax and chat about whatever you fancy.


Topic: Synth to 3D

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sir_ivar (Over 1 year ago)
I thought you might be interested in seeing an animation that I made showing a point cloud created from Photosynth and rendered in a 3D program:

http://www.youtube.com/watch?v=9-sjaUjrTnw

Hang in there for the 3D modeling, it's toward the end.  My videography skills aren't great but I think the results are pretty neat.
pope_luke (Over 1 year ago)
This looked really great. How long did it take you to make it? Was it very complicated?
TonyErnst (Over 1 year ago)
OK, that was really, really cool.  Well done sir_ivar.
sir_ivar (Over 1 year ago)
I was invited by Sul Ross State University and Big Bend National Park to document the Tres Yonis site a couple of months ago. The site consists a petroglyph covered boulder and a single pictograph.  

I started the project using coded targets from software called Photomodeler Scanner.  Basically, I attached a couple of hundred little paper target symbols all over the rock.  The targets allow Photomodeler to automatically determine camera orientation and expedite the photogrammetrical process of creating a 3D model.  That took a solid 12 hours of fieldwork/photography.

At the end of the day I noticed my focal length on my SLR wasn’t the same as it was when I started the day.  This meant that my focal length wasn’t consistent and consequently that Photomodeler would not likely be able to process my images!  Photomodeler requires that the geometry (i.e. all settings) of you camera stay the same during a photo shoot.  I had been focused on the rock art so intently
sir_ivar (Over 1 year ago)
that I had made a very simple and amateurish mistake.  All my days work was essentially wasted. This got me to thinking about Photosynth which is not dependent on camera geometry… 

So, the next morning I revisited the site and re-photographed the boulder as quickly as possible using the Photomodeler technique again but making sure my camera’s settings didn’t change.  That took about four hours. 

Before I left the site, I used my cheap Canon A590 to take pictures of the rock art with the goal of making a Photosynth mesh from it.  I took a little over 500 photos in about an hour.  I packed up, hiked WAY back to my truck and drove the 10 hours back home.

Once at back home, I started using Photomodeler to create a point cloud and 3D model.  I found that the software was having a lot of issues creating a 3D model as complicated as the Tres Yonis boulder.  Not only that, it was taking hours and hours to process the data.  I moved to Plan B and synthed the photos
sir_ivar (Over 1 year ago)
from my A590 and was really happy with the density of the point cloud.  After that, I grabbed the bin files and converted them to a PLY file and edited the point cloud for noise and such, exported the 3D model, and rendered it.  To get to your question, it took about an hour to take the photos, another 6 to 8 hours to generate the synth files (mostly upload time), maybe two hours to edit the point cloud and play with settings to get the best result, and another 30 minutes or so in the 3D program.

Let me say that I love both Photomodeler and Photosynth.  Photomodeler is capable of texturing the 3D model with photographs the model is created from (which is a huge asset). It also allows creates a model that is at a known scale. Just wanting to make sure that don’t come across as not liking Photomodeler or that I’m knocking it.  It’s an awesome app too.

Ramblingly yours…
Jonathan (Over 1 year ago)
well done. we love it when people get passionate about the possibilities with Photosynth.
Nathanael (Over 1 year ago)
Fantastic work, Sir Ivar. I'm always glad to come across people pushing the photogrammetrical angle and limits of Photosynth.
jlyon1515 (Over 1 year ago)
This is a great idea! How does one "grab the BIN files" from Photosynth, though?
Nathanael (Over 1 year ago)
Nathan.Craig (Over 1 year ago)
There is also the new and very easy to use Photosynth point cloud exporter.
http://pspcexporter.codeplex.com/

I use it, the application works very well. If the synth has many points (> 1 million), be patient and give the application some time, it will do the job.

Enjoy,
Nathan
Nathanael (Over 1 year ago)
Nathan, many thanks for the info! This is the first that I had heard of it.
sir_ivar (Over 1 year ago)
I revisited some old KAP photos and created a new 3D model/animation of an Inca "fortress" that I worked on in Ecuador.

http://www.youtube.com/watch?v=2-oK5lnNA-I

Thought you all might like to see it. -M
tbenedict (Over 1 year ago)
Awesome!  Is this done using the same workflow you posted a few months back?

Tom
sir_ivar (Over 1 year ago)
Tom, the methods were slighly different.  Here is what I did for the animation:
1) captured photos with KAP rig
2) processed and uploaded the data to Photosynth
3) grabed the point cloud
4) manually cleaned up and transformed the point cloud in VRmesh Studio
5) exported the cloud to ascii
6) imported the ascii file into arcgis and georeferenced it
7) exported as 3D points with the new georeferenced coordinates
8) imported the new points back into VRMesh Studio
9) meshed the point cloud in VRMesh Studio
10) exported to obj
11) rendered in 3ds Max

-Mark
inveritest (Over 1 year ago)
Mark, thanks for posting your process.  Your work is very noteworthy and an excellent use of Photosynth.
Nathan.Craig (Over 1 year ago)
Mark,

Looks great. Thanks for sharing your work flow. Here are the procedures I'm using to get the point cloud into real world coordinates.

http://www.personal.psu.edu/nmc15/blogs/anthspace/2010/02/structure-from-motion-point-clouds-to-real-world-coordinates.html

Regards,
Nathan
Akeem (Over 1 year ago)
Hi there,
the export process runs smoothly, but after importing the ply into meshlab I run into problems with stray points in the cloud. Is there any way to find and delete such points automatically?

Regards,
Achim
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