CGAL users discussion list

["Santosh Tiwari" <>]

Apparently, it is possible to generate a mesh from point cloud data using
CGAL.

If you have oriented normals, you can use Poisson reconstruction to get the
surface mesh.

If you do not have the surface normals, you can use the following software

http://www.den.rcast.u-tokyo.ac.jp/~yu-ohtake/software/index.html

The paper describing the software (algorithm) is "An Integrating Approach to
Meshing Scattered Point Data".

However, both of the above mentioned mesh generation methods have a
limitation. These methods will work only if the noise in the data is small,
i.e. if the noise is much less than the spacing between the point cloud
data. If the noise in the data set is of the same order as the spacing
between the data points, the output mesh will be useless. You can still get
a reasonable coarse mesh from the point cloud data.

Here is what I am doing to get the mesh from a noisy point cloud data.

1. Generate a regular alpha complex (3D alpha shape) from the point cloud
data.
2. Use Mesh smoothing techniques. I implemented the laplacian smoothing to
reduce the noise.
3. Generate point cloud data from the smoothened mesh.
4. Generate the mesh from the resulting point cloud data.

I cannot use the alpha shape directly since, the output mesh has many
imperfections.

Also note that, the alpha shape code will not work for more than 1 million
points on a 32 bit machine because of memory requirements.


__
Santosh Tiwari
EIB-326 Clemson University
http://www.clemson.edu/~stiwari/




-----Original Message-----
From: Pierre Alliez 
[mailto:]
 
Sent: Monday, March 24, 2008 10:57 AM
To: 

Subject: Re: [cgal-discuss] Mesh Generation from Point Clouds

hi Andrew,

I guess you are talking about mesh reconstruction from point sets?

we are working on it - but nothing before the next release.

in the meantime - if you have point sets with oriented normals I recommend
http://www.cs.jhu.edu/~misha/Code/PoissonRecon/

best,

Pierre

Andrew Corcoran a écrit :
>
> Hi there,
>
> I''m currently using the 3D alpha shape triangulation package in CGAL 
> to do mesh generation for point clouds. However alpha shapes don't 
> seem to deal with concave surfaces or large abrupt concave angle 
> changes in a visually pleasing manner.
>
> I've come across several commercial packages that seem to do this but 
> nothing thats freely available. I was wondering if there are any plans 
> to implement other meshing algorithims for point clouds rather than 
> just Delaunay and Alpha in CGAL or if anyone knows of another 
> free/open source package that has implemented slightly more robust 
> point cloud meshing.
>
> Thanks
> Andrew

-- 
Pierre Alliez
INRIA Sophia Antipolis - Mediterranee 
http://www-sop.inria.fr/geometrica/team/Pierre.Alliez/
Tel: +33 4 92 38 76 77
Fax: +33 4 97 15 53 95

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