Point cloud section


I would like to generate raster sections from the point cloud and export them as dxf. My clients program doesn’t support point clouds so I would like to generate dxfs with rasters as a workaround. I tried to use Pointcloudsection ( PointCloudSection | Rhino 3-D modeling ) but Rhino freezes. I have quite powerful computer so it is not a hardware problem. What can I do to make it working?

Hello - hard to say without the file - is the pointcloud very large? What settings in PointCloudSection? (Distance to plane, etc)


The cloud is 1,5 GBs and the parameters are as in the image:

Unfortunately, I can not send the cloud but I can tell that this is the elevator shaft and it consists of 46 000 000 points.

I think CloudCompare has a section tool for point clouds.

Yes, but you can generate the sections as images. The client has to manually scale them and put them in the correct position. This is the place for human error. If you can generate the drawings as dxfs, they should be placed in the correct place in the 3D space.

Check the CloudCompare documentation, I believe it can export the sections as DXF (probably polylines).


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I just tried the section tool in CloudCompare again,
it works very well !!

I do a lot of 3D modeling from large pointclouds,
You can also trace the sections manually using the technique I describe below.


Thank you @cdordoni for pointing me again into Cloud Compare. I was able to export a small part of the cloud as dxf. It is not a raster but will do for some time.

Thank you @Mike_A for your solution. Unfortunately, manual editing is not an option. I would like to generate images and put them in the correct place with dxf like it is done in PointCab or Register 360.

I’m curious why you need the section as an image file?

I would think the polyline sections would create a much smaller and responsive file than converting each section to an image, especially if the images needed to be high resolution.

I suppose if you only needed a few section a high resolution image would not be that bad. Hundreds of sections converted to high resolution images would likely result in a very slow interactive display.

Because my client’s program cannot import and display point cloud but it takes the raster image.

I hoped to achieve something similar to PointCab: PointCab Origins – Create Section - YouTube

I think the confusion is coming from the word “raster”.

Initially I though you meant an image file. However, based on your example, it actually appears to be a very thin selection of the scanned data points.

Do you want an image file or a point selection?

What program is your client using to view the sections?

The Cross Section tool in Cloud Compare can extract multiple thin slices of points from the entire point cloud.
Then you can export the slice(s) of points to a DXF.
I just tested this, see image below in Cloud Compare.
Then I imported the DXF with the points into IntelliCAD, see image below

I think you will need to take the discussion to the Cloud Compare forum for additional guidance if you are looking for a different function

If you actually need an image file (pixels) of the slices that will complicate the process for many reasons.

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Thank you @cdordoni for your help.
Indeed, when I say “raster” I am talking about the image files and this is my ultimate goal.

However, after your first post, I managed to create thin slices of the point cloud and export them as dxf. In the client’s program (ZWCad) they were turned into regular, CAD points. I am afraid that this is only a temporary solution because no program is able to store/display millions of points. It worked well enough for the slice in the XY plane but the one in XZ was too big.

What can I do to prevent Rhino from freezing when calulating point cloud section?

Your client should have a suitable application that can read point data.
Many CAD application can view point data, so that is not a problem.
If your client is using only a 2D CAD application then they need to get a better app, seriously.

Cloud Compare would not be able to create the images, and I’m not sure Rhino could do that directly.
You would probably have to export each slice one at a time to an image, and that would be time consuming and you would have to work out some method to ensure all the images are aligned precisely.
And the resolution of the images would be an issue as well.

The best thing for you do do is inform your client that they need a proper application to view and/or manipulate the data in a format that is not compromised.

It is your responsibility as a professional to inform the client of the limitations of their current process and recommend an industry standard solution.

Converting point clouds to image slices is not an industry standard solution for working with scan data.
It is poor work around for a process that need to be changed.

I don’t have a suggestion about Rhino freezing, other than its simply too many points for it to work with.
I suppose you could resample the points to create a smaller point cloud, so Rhino’s PointCloudSection might work.

I agree with all of your statements except the one about sections as images: some designers prefer the 2D slices. Maybe it is personal preference, maybe something else.

However, I don’t want to risk introducing too many changes to the current project. Changing the software is one of them. That is why I was looking for some simple workaround.

As for the Rhino freezing, the cloud is already resampled so I will wait for the McNeel suggestion.

Its not a matter of preference but of functionality.
Converting point cloud data to images is not a simple work around.

If the client insists on using a process that compromises results or results in ineffective effort, it might be time to find another client.

I work with pointclouds of up around 300,000,000 points every day in Rhino, if I need more I use the Veesus plugin.
I thoroughly agree with the comment below.

Most big engineering firms etc use Cloudworx for Autocad, or Bentley Microstation or similar, these are very expensive and very clunky as far a modelling goes. Even Revit is horrible as far as real modelling goes.

Rhino is a great solution for modelling from pointclouds, and relatively cheap.

My two cents worth… Mike.