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TBC v5.30 - Position and rotate pointcloud

  • 1.  TBC v5.30 - Position and rotate pointcloud

    Posted 06-08-2020 01:32

    Yesterday, I've tried to position a pointcloud. Somehow, I have a scan with no coördinates (total station has no coördinates). In fact, in this case, it was a good thing, because it was a standalone scan which I had to position into a greater scan, but without the necessary overlap. So, I calculated the position (and rotation) it had to have based on other measurments. In the scan I have two point: the position of the total station and the opening direction (which is displayed by a point with coördinates in TBC). I've exported this line (two points you know) to my CAD software to calculate coördinates for both points. I went back to TBC and entered these coördinates in these points.

    That doesn't work. After entering the first point (and recomputing of course), the pointcloud is in the correct position, but not the correct oriëntation. Then give the second point (oriëntation point) coördinates and recompute. Strangely enough, now the second point is correctly positioned, but I don't think the cloud is rotated, so the coordinates of the first point have changed.

    Ok, let's try this another way: "Transform Survey Points". Same steps, but now I get a gigantic "H Residual", what is not plausible or possible, since the distance between the original coordinates and the calculated coordinates is exactly the same. I've checked the distance in my CAD-software and in TBC to be sure. If I do the transformation, I get the same onlogically result as in the first method.


    Am I doing something wrong, or is this a bug, or even a limitation?

  • 2.  Re: TBC v5.30 - Position and rotate pointcloud

    Posted 06-08-2020 09:47

    Hi@Nico Louagie, seems that you have a few TBC issues clustered, the layer manager, the crashing, and the point cloud. Let me schedule a online meeting with you, so we can go through a few things all in one time. 

    Thank you.

  • 3.  Re: TBC v5.30 - Position and rotate pointcloud

    Posted 06-12-2020 01:40

    So, after an very interesting intervention of Rui (Thank you, Rui), an update:


    The fact the pointcloud did not rotate has to do with the so-called 'quality' of points: control, survey, mapping or unknown. In TBC higher quality will be preferred over lower quality. Data from a Total Station gets survey quality and in my case, the coördinates I enter are of "unknown quality". So, the survey quality gets priority: I can reposition the pointcloud, but not rotate it.

    Therefor I have to "disable" the azimuth (opening direction) of my first station:


    I hope my explanation makes any sense. 

  • 4.  Re: TBC v5.30 - Position and rotate pointcloud

    Posted 06-12-2020 09:22

    Hi Nico,


    Glad to help. Your explanation is exactly what happens in TBC. For your information, our senior engineer Troy Brown did a great TBC Power Hour to explain how TBC determines the positions of points. Here is the link if you'd like to watch it: