pystl

[Peter Otten]

Poul Riis wrote:

> I tried the following:
> 
> from pystl import PySTL
> with PySTL('stl_test.stl') as stl:
>     stl.add_triangle((0,0,0),(1,0,0),(0,1,0))
> 
> I got the following error message:
> 
> Traceback (most recent call last):
>   File
>   
"C:/Users/pr/AppData/Local/Programs/Python/Python35-32/Lib/idlelib/pystl_module_test_1.py",
>   line 3, in <module>
>     with PySTL('stl_test.stl') as stl:
>   File
>   "c:\users\pr\appdata\local\continuum\anaconda3\lib\site-
packages\pystl\pystl.py",
>   line 62, in __enter__
>     self.write_stl_header()
>   File
>   "c:\users\pr\appdata\local\continuum\anaconda3\lib\site-
packages\pystl\pystl.py",
>   line 75, in write_stl_header
>     self.f.write(struct.pack("80s", header_str))
> struct.error: argument for 's' must be a bytes object

You can fix this particular error by replacing the line

            header_str = ''

with 

            header_str = b''

in the write_stl_header() function which then becomes:

    def write_stl_header(self):
        if self.is_bin:
            header_str = b''
            self.f.write(struct.pack("80s", header_str))
            self.write_num_triangles_bin()
        else:
            self.f.write('solid ' + self.model_name + '\n' )

As this kind of error indicates that the module is primarily used/tested in 
Python 2 there may be other similar problems.