How to create cutouts and tolerences for this mesh?

[graham_S_allen]

I am still fairly new to Fusion but I know the basics like how to use offsets when creating sketches or offset face for solids to reduce the size of a body to the desired size to "fit" into a the cutout. However, I am unsure how to do this with a mesh I bought from the Internet. I know I can scale the objects but this is not the same as creating exact offsets for the shape of the objects, and it is also problematic because if I scale around the wrong focal point (I may be using the wrong terminolofy here but you get my point) the offset might be wrong around some parts of it.

How is the best way I might go about doing this for the below mesh?

For background, the mesh was originally one body, but the eyes and mouth were separate "entities" (but it was still one STL file) that went "into" the face (the bodies intersected), I so used Mesh > separate to create separate bodies, then used  assemble > cut to get the desired effect. I know need to offset the eyes and mouth slight by 0.2mm so they will fit into the grooves.  The idea is that I want to 3d print these items separately using different colours then stick them together when printed. The cuts are flat also, so they will print fine (the mouth cutout does not look flat from the below, but it is).

I can probably scale the eyes easy enough by scaling arond the diamater, but the part I can see me having problems with is the mouth, because ideally I need the lips (on the outside, and inside) need to be offset, and I don't know how to do this.

[marcus.toepke]

Hey!

In this case you don't need a scaling!

Try use offset to shrink the surface along the surface normals

[graham_S_allen]

I can't do that. As I said in the title, it is a mesh. You can't use those tools on a mesh, only on a solid.

[marcus.toepke]

And if you convert the mesh into a solid first?

[graham_S_allen]

I did try that already, but it's not helpful because it still has the same amount of faces as the mesh. So you don't get a clean "one" face perimeter like in your example pic - you end up with thousands of triangle faces (just like a mesh) and the offset face command can't compute it on all of them.

[laughingcreek]

in the mesh menus there is an option to shell a mesh body.

-shell the mesh, setting the thickness to be the amount you want the offset to be.

-separate shells.  this will separate the original outer surfaces from the new inner surfaces, so you will have 2 mesh bodies now.

-remove (not delete, or just turn the visibility off) the original outer surface.

-select the entire inner surface and reverse normals

[graham_S_allen]

In the end I had to recreate the mouth myself in Fusion using a sketch, extrusion then fillet. The tools for editing meshes simply aren't good enough in Fusion

[TrippyLighting]

Fusion is CAD software that works with analytical and NURBS geometry under the hood. The mesh modeling tools in Fusion are primarily aimed at preparing mesh geometry for conversion to BRep or surface models.

A better alternative for editing meshes are software packages aimed explicitly at mesh modeling, such as Autodesk Meshmixer or Blender.

[hfcandrew · Accepted solution]

As I find myself writing  this the thousandth time: If you have a mesh, use Meshmixer.

Fusion is like a kids toys for meshes, like an "easy-bake-oven". Sure it makes a cookie, but no pastry chef would use it.

Anyways in Meshmixer just:

1) Auto generate a facegroup: https://help.autodesk.com/view/MSHMXR/2019/ENU/?guid=GUID-5E91C94A-1D1B-46D4-BF09-776BE74F12A3

2) Select your facegroup then offset: https://help.autodesk.com/view/MSHMXR/2019/ENU/?guid=GUID-749E6C72-D82B-4FA9-A157-1AE612B779AE

[graham_S_allen]

Thanks. I am new to all of this so didn't even know about Meshmixer. I just googled it and looks like it will do the job. thanks!