merged point cloud (natural+artificial) doesn't create DEM from artificial area

[mjoaoh]

Hello

I made a photo survey of the roof of a factory.

1. Some areas are almost white and, for this reason, there are few tie points. The DEM that is generated has gross errors. The flat white areas have holes in it. This is natural taking into account the large areas (some square meters) of the point cloud without points.

So my idea was to create the point cloud of those areas. Because they have regular shape format based in vertical triangles and from the point cloud is possible to get the  coordinates of important points to generate the roofs, I recreated some of the white roofs and merged it with the natural point cloud (made it in Cloudcompare).

So I have a mixed point cloud: some areas have points from Metashape (natural points), others have calculated points (artificial). The DEM created by Cloudcompare is very logic, it makes sense.

In Metashape I delete the point cloud generated, and I import the new point cloud. When I generate the DEM I realize that it uses only the natural points. The area with artificial points (a point every 10cm) is blurred like it has no points to create the DEM.

I tried to solve: classify all the points as ground; I verify if the cloud was inside the region; I inverted the normals; in Cloudcompare I recoloured the cloud to a unique colour. No results

Need help

Kind regards

Maria Henriques