STL file opened in Tinkercad differs from same Mesh imported into Fusion 360

[Anonymous]

Whenever I import an STL as a Mesh into Fusion 360 it imports just fine, but when I import that same STL into Tinkercad it has additional artifacts such as blocks added to it.  I've attached two pictures of a car.  Look at the bottom of the car. The one from Fusion 360 shows a flat bottom of the car.  The same STL imported into Tinkercad shows big, square blocks on the bottom of the car.

The only reason I need to open these files in Tinkercad is I need to isolate different parts of them for 3d printing, such as each wheel and tire, and I don't know how to do that in Fusion 360 but I can in Tinkercad.  I can split an object in Fusion, but only on a plane.  I can't yet "extract" an object like a tire, that's why the need to open files like this in Tinkercad.

Anyone have any ideas why the reason for the additional artifact between the two programs for the same files?

[jeff_strater]

@Anonymous, it looks to me like the version in Fusion is correct.  I'm not sure what Tinkercad does with STL file import, but it looks like it is adding geometry that is not in the STL.  Have you loaded this file in some other tool, say Meshmixer, to see how it imports this data?

[Anonymous]

No, but that's a great idea. I'll try that in a few minutes and see what happens.

[Anonymous]

Opening in Meshmixer shows the correct object just like Fusion.  Still can't figure out why Tinkercad opens incorrectly.

[Anonymous]

I have also encountered import object corruption of a simple box that needs some minor modifications before print. I think someone at autodesk needs to investigate.

Object here: https://www.thingiverse.com/thing:1518257

Object import corruption in question: LEVEL1.STL

[laughingcreek]

This not being a tinker cad forum, there aren't a lot of tinker cad users here that are going to be able to help.

The file you referenced has some issues with the way it was constructed.  the legs are separate shells from the main drawer component, and they are nearly, but not perfectly, aligned with the drawer, creating a series of almost, but not quite planer faces that generally confuses modeling software (ie, the modeling work was a bit sloppy).  tinker cad will try to automatically repair issues with files when it imports them, but sometimes it needs some help. even mesh mixer didn't want to properly repair it.  I was able to get "sorta" ok results by using mesh mixer to separate the shells, and then importing the drawer and the legs (the legs can be done as a single group) into tinker cad separately, re-positioning, and the grouping.

of course, being a fusion user, I would just remodel such a simple design in fusion.  the process would be quick, and I'd end up with nice clean geometry.

[Anonymous]

Thank you for the explanation. Unfortunately I am having issues to get Fusion running due to higher computer requirements, so I am stuck using TinkCAD (that I love since it is simple for me as a noob to 3D printing and design).

It is interesting that when the original STL is loaded in cura or simplify3D they do view perfectly, so I was surprised that it failed to import in TinkerCAD. Possibly AutoCAD could provide some kind of toggle button on import to disable the auto correction if import corruption occurs.

Thank you again for the replay. I just found it today in my junk box, that’s why the delay in my response.

With kind regards & Happy Holliday’s!

Ken