Advice for creating a higher resolution point cloud from a CAD model?

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Advice for creating a higher resolution point cloud from a CAD model?

earnold2928
Hey everybody,
We're trying to convert CAD models (they're actually .stl files) into PCDs, however, there aren't enough points in the resulting clouds.

For example, we converted a simple cube to PCD, and it only was comprised of 8 points - each corner of the box - the minimum number of points to define a box.
Is there any way that we can convert the faces of the box into a point cloud, so that when viewed or compared to a 3D scan it isn't just literally 8 points?

Another example would be converting a sphere or any part with curves. Once converted to PCD, the curves are defined by a series of dots that make up the curve, however the curve isn't very smooth and is more polygonal.

I know it doesn't directly have to do with PCL, but do any of you know how to convert models into "higher resolution" point clouds? Is there a 3rd party piece of software we can use? Is there an intermediate file type we should convert to (we currently do stl -> ply, then ply -> pcd using the PCL converter)?

Thanks for your help! We're new to this so any advice would be appreciated.
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Re: Advice for creating a higher resolution point cloud from a CAD model?

andersgb1
Hi,

I usually load the STL/PLY models into Meshlab and then use the filter called Stratified Triangle Sampling with a million sampling points. This filter randomly samples the mesh surface. The 1M points is usually an extreme oversampling, but I use this to cover the surface well.

Then I save as PLY, convert to PCD using pcl_ply2pcd, and then finally use pcl_voxel_grid with a leaf size of, say, 1 mm to get a uniform and fixed resolution of the points. It usually works quite nicely!

On Tue, Mar 22, 2016 at 9:01 PM, earnold2928 <[hidden email]> wrote:
Hey everybody,
We're trying to convert CAD models (they're actually .stl files) into PCDs,
however, there aren't enough points in the resulting clouds.

For example, we converted a simple cube to PCD, and it only was comprised of
8 points - each corner of the box - the minimum number of points to define a
box.
Is there any way that we can convert the faces of the box into a point
cloud, so that when viewed or compared to a 3D scan it isn't just literally
8 points?

Another example would be converting a sphere or any part with curves. Once
converted to PCD, the curves are defined by a series of dots that make up
the curve, however the curve isn't very smooth and is more polygonal.

I know it doesn't directly have to do with PCL, but do any of you know how
to convert models into "higher resolution" point clouds? Is there a 3rd
party piece of software we can use? Is there an intermediate file type we
should convert to (we currently do stl -> ply, then ply -> pcd using the PCL
converter)?

Thanks for your help! We're new to this so any advice would be appreciated.



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Re: Advice for creating a higher resolution point cloud from a CAD model?

earnold2928
Dude, you're a hero.

That was exactly what we needed, and we even had that program downloaded
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Re: Advice for creating a higher resolution point cloud from a CAD model?

VictorLamoine
Administrator
Hello,

Another solution is to use the pcl_mesh_sampling program on the mesh:
https://github.com/PointCloudLibrary/pcl/blob/master/tools/mesh_sampling.cpp

Bye