It isn’t uniform like you are thinking. The model itself, and its specific geometry, will impact the result.
Here is a reply directly from Bambu Lab devs:
You’re right, the step file is a solid model, but 3D printing requires mesh data, so it needs to convert the solid into a triangular mesh. There are performance and accuracy requirements here. Currently, we are using the triangulation algorithm provided by the OCCT library, which may have some errors.
I did another test with a more difficult model than my last test, and it did reveal some issues with the STEP to STL conversion.
Here are the objects. All created with Fusion 360. The STL ASCII (D) was the best when looking at the closeup of the base and tip. But when I did the slicer preview, they all looked the same.
(A) STEP
(B) STL generated by Fusion 360 Cloud
(C) STL by right clicking body and exporting as mesh, Binary set to highest quality
(D) STL by right clicking body and exporting as mesh, ASCII set to highest quality
Here is a close up of the bases:
(A) (B)
(C) (D)
Here is the close up of the tips:
(A) (B)
(C) (D)
Maybe Bambu Studio needs a “settings painter” toolbar button, one that works the same as “format painter” in office apps.
It’s interesting that the base of the STEP looks worse to me, but the tip might be the best.
It just goes to show that there is a large variance in the output quality of different meshing algorithms, depending on the specific (local) model geometry.
I think the moral of the story right now is this:
Don’t assume that bringing a STEP file into Bambu Studio / Orca will give you better quality. It almost certainly will be worse. If you have access to a real solid model (like a STEP), then use your favorite CAD / translation software and settings to create your mesh file. You will have the best control and best quality this way.
A couple of days ago, I made a first prototype for an insert into my car to prevent my phone from sliding around. The color won’t be green in the end, I was just using that filament for my test pieces.
I exported a STEP file from Fusion 360 and this is one side that was rendered properly in Orca and Bambu Studio, it has a fillet in the top edge:
This a different side was rendered in the slicer, it was the same height, but a little wider and had the same fillet, part of it was ok, but the rest looked like this:
I then exported an STL file from Fusion 360 instead and it rendered properly.
