Quality check of DWG VS. Pointcloud

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gilles_3DR
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Re: Quality check of DWG VS. Pointcloud

Post by gilles_3DR »

Malte,

here is the procedure I would suggest in 3DReshaper.

My assumption is that the input data are:
  • a section in Z from the drawing department
  • a point cloud
Step0.png
Step 1: From the section, I would create a clipping plane of 10 cm height at the level of the section (this is purely for visualization purpose).
Step1.png
Step 2: From the section, I would create a mesh (extrusion of the section) of 10 cm height (next image is a detail view of the first one).
Step2.png
Step2-bis.png
Step 3: You can then run an inspection of the point cloud against the mesh.
Step3.png
In the inspection rendering, I have set the colors to show:
  • in light green, deviations between -1 cm and +1 cm
  • in dark green, deviations between -2 cm and -1 cm
  • in orange, deviations between +1 cm and +2 cm
  • in blue, deviations between -5 cm and -2 cm
  • in red, deviations between +2 cm and +5 cm
  • in grey, areas where no point did project onto (or too far)
In this inspection, if everything is green, everything ok. However, if you have large areas of other colors, then, a deeper investigation needs to occur.

Until this step, everything can be automatized/scripted in 3DReshaper (including evaluating the size of what is a large area). This means that large areas of errors can be automatically extracted for deeper investigation.

This inspection highlights 2 large areas (one in grey - first image below and one in orange - next image below). In these areas, the drawing do not fit the +/-1 cm expected accuracy.
Step3-bis.png
Step3-ter.png
Looking forward your feedback.
If you want some help for automatizing the procedure, let me know!
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MalteHC
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Re: Quality check of DWG VS. Pointcloud

Post by MalteHC »

This is very smart to check a floorplan where the Z-axis doesnt deviate, but if i got something like a curb, it wariates in the Z-axis and the line i want to check is in the top corner on the curbstone. How would you check that? Keep in mind, that we are talking roadscanning, so the complete pointcloud can easy be 300 gb, if it isnt devided in sections.
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gilles_3DR
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Re: Quality check of DWG VS. Pointcloud

Post by gilles_3DR »

Thanks for the PM Malte,
I will answer to your questions!
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Re: Quality check of DWG VS. Pointcloud

Post by gilles_3DR »

All,

I had some private discussions with Malte as the need is different to what I initially understood. And I think what came out of these discussions are helpful to everyone!

The proposal is to use the clipping planes in 3DReshaper. Actually, these are very powerful tools as:
  • Clipping planes can follow a polyline. To do so, select the polyline before launching the View / Clipping plane tool. When you will move the clipping plane, it will follow the polyline (ie in 3D).
  • You can define depth of clipping planes to create slices. For curbs application, maybe 2 m?
  • Moving the clipping plane can be done using the mouse wheel at any time: select the clipping plane and use Ctrl + Mouse wheel. It will move according to a given step.
  • By default, the step for moving is automatically defined according to the current zoom. You can set it to a user defined value. Setting it to 2m (ie the same value as the depth) allows to move the clipping plane along the polyline of the same value as its depth
  • A view port can be locked to a clipping plane. This means that the view will always be perpendicular to the path. This is done using the little lock (see image below)
    lock.png
  • In the locked view, you don’t need to select the clipping plane to make it move step by step: just use Ctrl + Mouse Wheel
  • Splitting the view in 2: 1 locked and one not locked allows to see where the clipping plane is.
Of course, all this works with a “CloudWorx” cloud. This means you can visualize very large dataset from JetStream for example to QA your drawings.
Views.jpg
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