Point clouds are supported in some formats such as PLY, DXF, ASC (text), VRML, OBJ, 3DC and LAS.
ASCII text files should be formatted with one vertex per line, optionally with RGB color information:
x y z r g b
We process point position and color, but we do not currently support other flags in the file like point size.
You can set a size for all points in 3D Settings.