Drape question

Offline bigroo over 9 years ago

Hello all,

I am very new to Descartes, the version I have is SS5, I have point cloud data of a railway cutting with a tunnel and I'm attempting to drape an element on to the surface. The thing is I have been given all of the point cloud data on one level and cannot separate out the vegetation. Hence when I drape I get tree lines mixed with terrain.

My question is can I drape from underneath to get the profile of the ground?

All the best,

Michael

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0 Offline Mathieu St-pierre Thu, Oct 16 2014 4:03 PM
Hi Michael,

I could suggest two solutions to solve this problem.

1) Clip out the vegetation with the point cloud clip tool then drape.

2) Draw the element near the ground and set a small value (a value smaller than the distance between the element and the trees) for the Height option in the Drape Element tool settings then drape.

Thanks,

Mathieu
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0 Offline Mathieu St-pierre Thu, Oct 16 2014 4:03 PM
Hi Michael,

I could suggest two solutions to solve this problem.

1) Clip out the vegetation with the point cloud clip tool then drape.

2) Draw the element near the ground and set a small value (a value smaller than the distance between the element and the trees) for the Height option in the Drape Element tool settings then drape.

Thanks,

Mathieu
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0 Offline bigroo Fri, Oct 17 2014 3:38 AM in reply to Mathieu St-pierre

Hello Mathieu,

Thank you for replying, I will give it a try but I'm not sure how effective or easy it will be as the ground profile is a cutting (V shape) and not level hence the height option and clip may experience difficulties.

I'll keep you informed.

Michael
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0 Dan.McKenzie Fri, Oct 17 2014 9:29 AM in reply to bigroo

Hi,

Is your pointcloud classified? If so you can turn off the vegetation using the Presentation style manager and the element you want to drape will only take the points that are visible in the view you selected.

Thanks,
Daniel
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0 Offline bigroo Mon, Oct 20 2014 3:58 AM in reply to Dan.McKenzie

Daniel,

Everything is on the default level and undefined.

Michael
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0 Dan.McKenzie Wed, Oct 22 2014 3:03 PM in reply to bigroo

If nothing is classified you will need to try the 2 options Mathieu suggested, you could also try to classified your pointcloud but it will give the same result as if you clip the useless points.
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0 Offline Jovan_Djukanovic Sun, Nov 2 2014 9:37 PM in reply to Mathieu St-pierre

Have you tried using the Snap Element tool (rather than Drape Element) which it would seem to me does a form of draping anyway? This video shows how you can use the Snap Element tool to move elements onto an underlying surface, in this case a surface under a bridge. I'd imagine it might be able to account for trees if there are also surface points.

http://www.youtube.com/watch?v=u6p5MNFr9PY
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