Question on 3D printing cylinders

Devon_Sinsley · February 10, 2022, 2:59pm

So in Fusion at least when I draw a cylinder it draws a nice round cylinder. But when it prints it prints a polygon. Not a smooth cylinder. If I am correct, all CAD programs do this when you convert the file to an .stl (at least). Its a translation issue if I understand it correctly.

If this is not true then what am I doing wrong. If it is true is their a work around to make the cylinders smooth instead of faceted? One thing I tried was designing the part huge and then reducing the final product in hope that it would create more facets and then be less noticeable. That didn’t work.

If you can’t get it to print truly round, then can I increase the number of facets by creating say a 1,000,000 sided polygon instead of a cylinder?

manimal · February 10, 2022, 3:25pm

In Sketchup I just hold Ctrl and + to increase the # of sides in the circle while the circle tool is active. Maybe try that in Fusion? Or maybe just +

Devon_Sinsley · February 10, 2022, 4:11pm

So you basically are doing what I thought needed to be done. Just increasing the number of faces to smooth it all out. I kinda figured that maybe the route I had to go.

manimal · February 10, 2022, 4:31pm

Yes. EVERYTHING drawn in CAD is just made up of polygons. Maybe this is the cause of your issue though?

Steve_GScale · February 10, 2022, 4:34pm

I use FreeCAD and Cura, never had to tweak anything for smooth sides.
Here I created a 2" cylinder, with 1.9" interior. Exported as .stl from FreeCAD
and then opened with Cura. It would print as smooth as it looks:

RGSNH · February 10, 2022, 5:00pm

Devon,

look at your *.stl output options. you should be able to adjust the size of the triangles, make them smaller. at least i can in solidworks.

Al P.

rmccown-admin · February 10, 2022, 5:34pm

I’ll echo what everyone else has said, its the number of faces. These two wheels are 128 ‘sides’ and they come out pretty well.

manimal · February 10, 2022, 5:51pm

Bob, Are you using Fusion 360? It seems you can create a circle with a ton of faces but then when you export as an STL, Fusion will decrease the number depending on your settings. Export STL from Fusion 360 for 3D Printing - YouTube

rmccown-admin · February 10, 2022, 6:02pm

There I created in Tinkercad with the face count I wanted.

Devon_Sinsley · February 10, 2022, 11:31pm

Hey thanks for that. Maybe that will solve or at least reduce my issue.

manimal · February 11, 2022, 12:45am

Curious to know what it was set for as a default? Medium?

Devon_Sinsley · February 13, 2022, 10:12pm

I haven’t been back on to look into it. I have had a crazy last couple weeks. Between a family with COVID including me, my daughter, her husband, and four month old. Thankfully no one had anything worse than a bad case of the flu. And right after that my poor daughter gets a 7mm kidney stone. So they all moved in with me while my wife was on a cruise and I nursed everyone back to health. She had it blasted and now everyone is healthy and happy.

So hope to revisit this soon.