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RANSAC SD crash

Posted: Wed May 27, 2015 11:37 am
by sguinard
Hello,

I'm new with CloudCompare, and wanted to try RANSAC plugin in order to detect trunks in a point cloud.
The problem is that I can set the parameters but it seems that the software freezes just after that.

Could it be linked with the size of the point cloud ? Or is there an other cause ?

Re: RANSAC SD crash

Posted: Wed May 27, 2015 12:25 pm
by daniel
Does the software actually crash or it just freezes?

And what is the size of the cloud? (because yes, it can take a while, especially if the plugin needs to compute the normals first).

Re: RANSAC SD crash

Posted: Wed May 27, 2015 12:34 pm
by sguinard
Thank you for the reply,

Actually it just freezes

My point cloud contained 5 000 000 points but when I try with a 1 000 000 one it works in 30 seconds so I guess the size is the main cause ...

Re: RANSAC SD crash

Posted: Wed May 27, 2015 12:43 pm
by daniel
Yes the code used by the plugin is the original one (from Schnabel's library: http://cg.cs.uni-bonn.de/en/publication ... efficient/). Therefore it's a research work (even though it's already quite good and no real bug has been found yet).

Re: RANSAC SD crash

Posted: Thu May 28, 2015 9:12 am
by sguinard
Thank you !! I just have an other question :

is it possible to add a filter or something like that, in order to select only the most interesting results ?

Best regards

Re: RANSAC SD crash

Posted: Thu May 28, 2015 9:54 am
by daniel
Not really. You can only select the type of entity.

And it would depend on what you call 'interesting' anyway ;)

Re: RANSAC SD crash

Posted: Thu May 28, 2015 11:10 am
by sguinard
What I was thinking about is, in my case, keep only cylinders that have a certain radius.

If it's not possible, do you think I'll have to integrate my own functions to RANSAC plugin ?

Re: RANSAC SD crash

Posted: Thu May 28, 2015 12:52 pm
by daniel
Yes, I think it would be the best way. And you get something working (even in a dirty way) we can integrate it afterwards.

Re: RANSAC SD crash

Posted: Fri May 29, 2015 7:44 am
by sguinard
Hi Daniel,

I think I'll work on it soon,
I just also need to know if it is possible, once you obtained 3d primitives via RANSAC plugin, to segment your point cloud using those primitives ?

Re: RANSAC SD crash

Posted: Fri May 29, 2015 12:21 pm
by daniel
Well normally the plugin output the subset of points corresponding to each primitive

But you could also compute the distances between the whole cloud and the primitive to segment the points below a given threshold distance.