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Topic: Reducing number of points in pointcloud

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Kjellis85 (Over 1 year ago)
I am trying to create a 3d model from the pointcloud extracted from one of my synths. I'm using meshlab to generate the mesh, but because of the sheer amount of points in the cloud it seems that meshlab, and my computer for that sake, struggles and eventually crashes. Is there any way to reduce the number of points in the cloud after exporting it so it becomes easier to handle? I do realize that an easy way would be to reduce the number of images used, but then the resulting cloud would loose detail. Also, are there any alternatives to free software one could use to edit the pointcloud? It might be just that I'm a total noob at meshlab, but the gui and editing capabilities seems a bit hard to get around.
Nathanael (Over 1 year ago)
Hello, Kjellis85.

A couple of things for you to try: 

1: Reduce the resolution of the input images to anything lower than 1.5 megapixels before synthing.
(Although Photosynth always uploads the full resolution images, it only uses 1.5 megapixel copies of all the images that are larger than that limit in order to perform the matching, so you'll have to shrink the input images to be smaller than this limit before you'll see a difference in the point cloud.)

2: Use Henri Astre's Photosynth Toolkit: 
http://www.visual-experiments.com/2010/08/19/my-photosynth-toolkit/
http://www.visual-experiments.com/2010/08/22/dense-point-cloud-created-with-photosyth-and-pmvs2/
Editing the 'Level' setting in the pmvs_options.txt in Step 4 of his workflow will allow you to select the resolution that you want to generate a point cloud at. Level 0 is original resolution and every higher number is a lower resolution.
Nathanael (Over 1 year ago)
Henri's toolkit also uses a standalone tool to convert point clouds to meshes.
Kjellis85 (Over 1 year ago)
Thanks Nathanael, will give it a try. I'll post my findings :)
Kjellis85 (Over 1 year ago)
Well I'll be darned!! It finally worked! And it wasn't that hard. Now, if someone could bake all of this into one program with an easy GUI my master thesis will practically write itself (just kidding:P). Sadly I have the programming skills of a chipmunk, so I don't see myself programming anything in that direction anytime soon. If you think you might know anyone who is thinking about doing anything like that, let me know, I will greatly appreciate it:)
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