Plane through quay wall for colouring

[sampie]

Hi,

I have a multibeam bathymetry dataset (x,y,z) of a quay wall. The dataset is quite dense and the quay wall consist of piles. the aim is to find irregularities in the quay wall. As the wall is almost vertical it would be nice to be able to draw a plane through it to calculate the distances in front and behind the plane. Or to be able to colorize referred to this plane and not to the standard x, y, z axis. Attached is an image.

Is this possible and if yes, how to do?

Thanks,
Samuel

[daniel]

Quite easily:
- Segment (some of) the points belonging to the wall with the scissors tool
- Select the subset of points and fit a plane (Tools > Fit > Plane)
- Select the plane and the cloud and compute the distances (Tools > Distances > Cloud to Mesh dist.)

[sampie]

Thanks for the help, it works quite well and it is what I want.
However if I use the scissors to segment I can only do it with the data visible at that moment. If I want to to my whole dataset then i have to zomm that far out that I don't have enough details to put the polygon correctly.
Is there a way to zoom in, start with the polygon, pan, go on, pan, go on, pan, go back, ... So enough details (zoom in) to make a good polygon and pan through the dataset to be able to make one polygon for my complete dataset?

Thanks

[daniel]

For now you can't move the viewport while drawing the polygon.

But:
- you can reverse your process and remove the points at the border of your wall. You can apply the cut (don't close the tool), then move the viewport and draw a new polygon (with the first "pause / unpause" button). Repeat the process all around the whole.

- otherwise it's not always necessary to be ultra precise on the cut as the plane fitting is a statistical approach and the few points you add or miss won't necessarily change the result in a significant way). But of course it depends on your cloud ;)