Help cutting mesh along a line (Star Wars Cosplay armor for my daughter)

[ryannosaurus]

Hello all! I've got a project I'm working on my daughter with. We're working on some Star Wars cosplay armor to 3D print. Attached is a screenshot of the chest piece. We've got it tweaked and sized to her, but I need to cut it into two pieces so she can put it on.

The first cut needs to go down the side from the armpit to the waist (green line on pic). There's an existing raised section there in the print that I'm trying to cut along. (blue arrow on other pic). Unfortunately, I can't just do a plane cut that goes up through the shoulder area... that would be too easy! The second cut will be across the back, so just the back lower 1/4 of the armor comes off. (3rd pic just for reference.)

I'm really new to Fusion 360... I've plinked around in TinkerCAD and Meshmixer so I have general idea of 3D modeling, but have A LOT of learning to do!

I've watched some F360 beginner tutorials and some specific focused videos, but I'm stuck on this. I feel like I need to draw a line in a sketch on the mesh, then "split body".

But I'm getting hung up on the mesh section sketch. I try to create the mesh section sketch, but every time I do the sketch just disappears.

Can anyone help me understand if - first - this is the right process to follow? If so, why does the mesh sketch section disappear as soon as I hit OK?

Thanks!!

EDIT: Second question: if following that line precisely will be a major PITA, how can I just smooth/remove that lip completely so I can cut at will?

[hamid.sh. · Accepted solution]

Fusion is not suitable for mesh editing, but you might be able to do what you want with one of the following methods:

1. Plane Cut, then Combine mesh bodies that should have not been separated

or

2. Go to Direct Edit mode for mesh. Use mesh brush to select ALL the faces on one part that you want to be separated (PITA). Mesh > Prepare > Create Face Group to make a face group out of selected faces. Then use Mesh > Modify > Separate > All Face Groups.

If you share your mesh I'll try to show how to do the above.

[JeromeBriot · Accepted solution]

Use Meshmixer and its own "Plane cut" tool instead of Fusion 360.

Can you share the STL file?

[TrippyLighting]

Can you share the mesh file? (not the .f3d file, but the original mesh file)

[hfcandrew · Accepted solution]

You are looking for a plane cut of a selection: https://help.autodesk.com/view/MSHMXR/2019/ENU/?guid=GUID-54CCA26A-5A7D-46F4-A942-6A9DF1E2D7DE

Select the general area you want the plan cut to go through, make sure NOT to select an area you don't want cut > Edit > Plane cut

[ryannosaurus]

Thank you. I’ve seen the same sentiment - Fusion 360 is not good with meshes - so I went back to Mesh Mixer to do it. 

I’m trying to learn F360 for solid creation, but didn’t realize it wasn’t good for meshes too. 

Have a good day!

[ryannosaurus]

Thanks, I was learning F360 to create solids but didn’t realize it wasn’t the best for meshes. Too bad, I’d like to have one tool and environment for both. I went back to MM and did it there. Thanks!

[ryannosaurus]

Thanks for the reply! I ended up doing it in Mesh Mixer. Appreciate the offer to help!!

[ryannosaurus]

Thanks! I ended up going to Mesh Mixer and doing that same routine. It seems F360 is better for solids, and not so good with meshes? I was hoping to learn F360 to work with both in the same environment, but looks like I’ll be learning both. 🙂 Thanks again.