Remove overlapping point - z-Projection

[PeterV]

I have 2 clouds: 1 big inaccurate raster cloud and 1 small lidar cloud with high precision. Now i want to cut out from the big DTM a hole where i have the higher resolution cloud and then merge the models.

So far i calculated the c2c distance and filtered out all points under 3 m distance, but the problem ist, where the models differ in height more than 3 m i have overlapping regions.
I also tried to compute separate x-y- and z values, than apply sqrt(x^2+y^2) and filter on that, but the result is not what i want, because the c2c distance is coputed in 3 dimensions.

Is there a method for computing the c2c distance only comparing the x-y coordinates alone? I would practically need a 2d-buffer around my z-projected cloud, without taking the z value into accout.
I also tried to compute the envelope-polyline of may small cloud and segment out the points with it. But if my small cloud has bigger holes in it, i would like to fill these with the coarse raster cloud.

[daniel]

Have you tried 'flattening' the clouds first?

1) Save the Z coordinates with 'Edit > Scalar fields > Export coordinate(s) to SF'
2) Use 'Edit > Multiply / scale' to multiply X and Y by 1, but Z by 0
3) Compute the distances (which should be done in 2D in a way?)
4) Restore the Z coordinates with 'Edit > Scalar fields > set SF as coordinate(s)'

[PeterV]

Thank you Daniel! This is exactly what i was looking for and works perfectly!!!