lines instead of points in geomagic ?

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Muaz
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lines instead of points in geomagic ?

Post by Muaz » Wed Jun 15, 2016 9:15 am

Hey

I am trying to import a point cloud from cyclone in .PTS format
For some reason the points are vanishing when i open them in geomagic wrap.
This is what i get and see (Attached image)

ven though the number of points are kind of big ? This is 1.5 m points .. does it make sense ?
am i doing some mistake while exporting it from cyclone ?

Thanks
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jekub
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Re: lines instead of points in geomagic ?

Post by jekub » Wed Jun 15, 2016 9:58 am

IMHO you're having some accuracy problems, looking at the image I can tell that the X coordinates in the point cloud are big numbers this means less space for the fractional part.

Try to translate the point cloud to the origin before exportation.

Muaz
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Re: lines instead of points in geomagic ?

Post by Muaz » Wed Jun 15, 2016 11:58 am

Hey Jekub,

I just checked the distance in x axis, the scale sounds good and the point cloud is registered to a national coordinate system. Those lines ? I measured the distance between them in wrap and it was around 1 cm .. which makes sense since this is the point distance i chose when I unified the point clouds in cyclone.

Still weird.. I tested to import the whole point cloud with 150 million points , same !

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Re: lines instead of points in geomagic ?

Post by jekub » Wed Jun 15, 2016 1:43 pm

Let me explain it again.

The problem is that it's registered to a national coordinate system and you end with values like these:

Code: Select all

      3139737.224          329049.087     80.407
      3139737.227          329049.069     80.403
      3139737.229          329049.056     80.403
      3139737.231          329049.041     80.403
The video cards works with 32bits floating point numbers for vertex coordinates, even if you send it as 64bit floating point data (I think that GPU internally uses 24bits numbers), so you end with values something like this (80 integer part is small enough to keep all fractional part)

Code: Select all

      3139737.2          329049.08     80.407
      3139737.2          329049.06     80.403
      3139737.2          329049.05    80.403
      3139737.2          329049.04     80.403
All X values lost most of the fractional part so it's looks vertical lines, have you tried to rotate the view? I bet that the points jump from one line to the other, you can't have points in the middle because there are no space for the fractional part.

IMHO it's a bug from geomagic, it should do the conversion from a global coordinate to a local one before it send vertex data to the GPU.

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Re: lines instead of points in geomagic ?

Post by Muaz » Mon Jul 04, 2016 1:52 pm

You were very right..

That was the problem .. Cloud Compare however can be used as a mean or tool to fix this problem before exporting it back to GeoMagic

Thanks alot !

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Re: lines instead of points in geomagic ?

Post by stevenramsey » Mon Jul 04, 2016 2:43 pm

Geomagic like many others can't handle huge coordinate systems. Set a new origin so the first 3-4 digits are removed from the coordinate system, making sure it is nice round numbers so you can shift the results back if you need to.
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