Fusion360 cam problems with .stl and .3dm files

[ricotte]

I am fairly new to Fusion360, but am now able to use the cam function to create gcode for parts I create in Fusion360.  My goal is to mill surfboard fins that are given to me in stl format.  I can import these files to Fusion360 as a mesh, but then I discovered that I could not use the cam function on them.  I tried the convert function, but received warnings about the large number of triangles, and it simply froze up.  I was able to get the file in .3dm format (someone else converted with Rhino), uploaded that, but Fusion360 simply freezes whenever I try to do anything, such as scale it to get it ready for cam. 

Does anyone know if it is possible to use the cam function on files like this?  I found the interface to Fusion360 cam intuitive and easy to learn, and am really hoping I can find a way to make this work. 

In case anyone is interested, here are links to the stl and 3dm files I was trying:
https://www.dropbox.com/s/7hmx5493jd4xdv3/finfoil4.stl?dl=0
https://www.dropbox.com/s/rzgiahfu5sfyxai/finfoilNURB.3dm?dl=0

I'm using Fusion360 on the Mac
Thanks very much, and I apologize if the answer to this is completely obvious to those less ignorant.
Ric

[Steinwerks]

I would try and get IGES, Parasolid or Step files, as they will be the most widely usable. STL's are very difficult as they are an approximation of a surface made up of triangles (or so goes my understanding).

[matthew.nichols]

I am with atomkinder67 on this one.  your best bet will be .igs or .step files.  I know inventor has an addin that helps to convert the mesh triangles in an stl file, but it's pretty rough.

are the original designs being done in Rhino?

[ricotte]

The original files are produced by a program (FinFoil) and stl is the only output offered.  I haven't found a converter that will convert an stl file into  iges or step files (a person tried to use Rhino to convert it to nurbs to see if that would help).  I may write the author of FinFoil about other export options, but for now, it's all there is.
Thanks.

[bobvdd]

Ric,

You could import your STL files in a free Autodesk program called Mesh Mixer
http://www.meshmixer.com/

That program has the ability to reduce the number of triangles in the STL file. The original STL file has over 50k triangles (way too precise for such a smooth shape BTW). Bringing it down to below 10k will make the Mesh to Brep conversion in Fusion faster and more successful.
See my first image.

The second image is a snapshot of the toolpaths during simulation.

Here is a link to a 3MB Fusion file, so you can see what I did.
Cheers
Bob

[matthew.nichols]

I didn't know that mesh mixer was for that!  That is awesome.  I have some woodworking files I can use that on.
Thank you for the informative post Bob!

[ricotte]

Bob,  That was very helpful!  I really appreciate the pictures and the file was especially helpful.  I learned a LOT from looking at your cam settings.

I downloaded MeshMixer and was able to reduce the number of triangles.  However when I import the result into Fusion360, my fin does not look like yours.  Your fin has much larger and smaller triangles in various places; there are some places where there are lots of small triangles, and others where there are mostly large triangles.  I'm not sure how you did that, and wondered if you consciously did it.  What I got out of MeshMixer was not like this. 

(with the cam, is there a way to have the outside 2d contour set automatically?  Your outside contour was very nice, and I difficulty getting anything like that at all.)

Thanks very much; I was about to give up, but now see that it possible (though will take a lot of practice on my part),

Ric

[bobvdd]

Ric,
My error that the triangles don't look even. I used a too small brush to select and probably did not select all the triangles.
Attached is a video on how I reduced 49k triangles to less than 8k triangles. And still I could have taken a larger brush to make my selection go faster 🙂

Bob

[ricotte]

Bob,

Thanks very much--the video really helped.  I think I've got it figured out now (I'm a bit slow).

Ric