Binary STL Files are recogniced as ASCII
[...] in the function _STLReader_::check_stl_type() (STLReader.cc file) you assume that a STL is encoded in ASCII format by looking for the keyword solid, i.e., line 476:
//check for ascii keyword solid
if(strnicmp("solid",&line[firstChar],5) == 0)
{
return STLA;
}
The problem is that also some binary STL files start with the "solid" keyword, and it seems the standard allows it, at least looking at the first references I've found:
https://people.sc.fsu.edu/~jburkardt/data/stla/stla.html
https://people.sc.fsu.edu/~jburkardt/data/stlb/stlb.html
[...]
a workaround solution could be to look for the keyword "facet" in place of the keyword "solid" [...]
by Alberto Pretto
Related to: https://www.graphics.rwth-aachen.de:9000/OpenMesh/OpenMesh/merge_requests/83
example file to trigger this issue: sportellino.stl