One of the most common questions I see throughout forums is how can one edit an STL file. I also have had this question over the last 2 years while working on my InMoov Robot as all the shared files are STL files. The source files are from SketchUp. I don’t have SketchUp since it became payware, I tried it when it was still owned by Google, but I didn’t like it much.
Anyways, after much searching and reading I found the typical method suggested which was to use FreeCAD. You can see that method here: https://grabcad.com/tutorials/how-to-convert-stl-to-step-using-freecad. However, I have had very limited success with this method. It may work about 40% of the time I used it. Now I did use this method and still do on occasion (Very very rare occasion), typically it is because I forget about another method I will soon mention.
Then I came across InStep V2, I have used this dozens of times and it has almost always worked for me. Success rate of 95% or more. This is also the easiest method.
Now recently I came across two videos by @productdesignonline you can visit his website here Product Design Online. Kevin is a great presenter and teaches in an easy to follow method. I have been following his tutorials for some time now. He is a member here in the forums and occasionally posts here.
I used his method with Fusion 360 about a dozen times over the last week while working on my InMoov Eyes Conversion. This method worked 100% of the time so far. But one of the things I really liked about Kevin’s method was when he showed how to merge the triangles on a plane to remove them or just make larger areas as one. This is priceless if you need to modify STL files, especially those that have flat surfaces.
In the end my favorite method of converting an STL file is using InStep V2 as it is simple and just works, I also like the method Kevin uses.
I hope this helps some of you out who wish to modify STL Files or convert them to STEP format.