Mesh buildings from Lidar point cloud

I am currently working on building modeling through the use of aerial scan data. I have to process a large amount of data contained in a lidar point cloud. I treat the soil, vegetation and buildings separately. At the moment I'm having trouble creating mesh for buildings.

However, if you have other suggestions I am open to them. After several tests and different techniques, the best solution seemed to me to define the points that make up the roofs and then extrude everything. However, I can not do it well. I miss a "Concave Hull" function that works well.

My questions would be:

How to find the points that make up the roofs?

How to create a surface from these points?

I also tried Nik's technique to get there.

(NIK'S ZBRUSH COMMANDER - http://www.grasshopper3d.com/forum/topics/zbrush-is-now-a-grasshopp...)

Here's the link to the point cloud txt file. https://www.dropbox.com/s/dixrrd3t80f1oj6/CloudBuild_Light.txt?dl=0

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Replies to This Discussion

Permalink Reply by japhy on November 1, 2017 at 7:20am

I, unfortunately, work with point clouds often. The best process i've come up with is to use cloudcompare (open source point cloud software) to segment and clean up the clouds, saving in smaller bites to .e57, which i then import into grasshopper via Volvox plugin. Depending on what i'm doing i will either bake the cloud or perform operations on it. Typically the cloud/plane intersection. This will give cuts that i can order points and average some curves.

Permalink Reply by Raphaël Désy on November 1, 2017 at 8:58am

Thank you for your answer !

I have already used CloudCompare to divide my point cloud into different classifications. I am also familiar with Volvox to import data into Grasshopper.

I'm not sure how to find planes and approximate curves. Would it be possible for you to join an example?

Thanks for your help.

Permalink Reply by japhy on November 1, 2017 at 9:19am

its not finding planes, its intersecting the cloud with a plane (volvox/analysis), to create a planar set of points (project option in the component).

you can then use various curve components to generate geometry; fit line, circle fit, polyline ect.

Its not easy getting clean geometry out of point clouds, too much fuzz.

Permalink Reply by japhy on November 1, 2017 at 10:35am

rough example

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