I downloaded an archive with STL files. And they are of very poor quality (Structural Components - Nominal Size (identical aluminum parts). They cannot be made independently. This is fine? Or are there other materials somewhere that I did not find?
Sorry if you wrote the wrong section.
im not sure what the issue might be, I have opened this same STL file in Cura and Solidworks and It appears to look OK, What version of Solidworks are you using?
I am using 2017 version SolidWorks . But it doesn't make any difference. I have opened files in different applications. The problem is that the curves are not arcs. Even in your drawing, you can see that the hole consists of planes. Which is extremely unpleasant when assembling a project, not to mention manufacturing a part. Why couldn't these format details be made STEP as in the next folder?
You can go to Solidworks options and then look for image quality and performance to bump the quality, it may fix your issue,
Also check when you open the file check the import options at the bottom near the file extension drop down on the file open dialogue box, sometimes there are option to improve quality in there.