Hello,
Yes, in principle it is possible to convert a solid into a skin in Netfabb using the lattice tool. However, as you've seen, the quality of the result is highly dependent on the geometric complexity. Speaking in extremes, a finely tessellated sphere is going to convert to a thin skin better than a roughly tessellated, highly technical part with sharp corners, tight turns, and narrow walls converts to a thick skin.
This is unfortunately a limitation that cannot be ignored. The workflow must adapt to either evade the limitation or work around it. For example:
- To evade the limitation, generate the inner surface (the cavity shell or shells) separately and combine it with the lattice in a later step.
- To work around the limitation, adjust the source mesh quality so that the skin generation in latticing produces satisfactory quality.
- Either way, while the skin preview highlights problem areas, it also tends to exaggerate. Try generating the component only using the skin definition to test the mesh generation. This may reveal that the result is actually not as terrible as the preview suggests.
- Still, expect to do some additional repair to clean up issues like self-intersections and floating noise shells.
- Use a solid, simplified version of the original part to generate the raw lattice. Merge it later with the cavity shell. Merge the latticed cavity shell with the original geometry.
- When merging meshes, prefer to have good overlap. If shells meet only at their surface, merging them can produce mesh anomalies and lack of contact. This can lead to flawed toolpathing, possibly even print failure.
To generate the inner surface separately you could use non-latticing tools like Generate shell. Or you could generate the inner surface by adding it to the design in Fusion before you send it to Netfabb.
To adjust the mesh quality, you could remesh (in mesh manipulation or repair) and smooth (mesh manipulation or repair) the mesh so that triangles are more regular and more evenly distributed.
Remember that this is only for generating the cavity shell. You can always recombine the generated cavity shell with the original outside surface shell so that you do not lose the original shape beyond tessellation of the source CAD design. Latticing and combining shells in Netfabb is always mesh-based and therefore inherently lossy and irreversible. I can only recommend to work with parametric, or CAD designs as far as possible through your workflow. Netfabb does load CAD files (STEP, IGES, etc; for full list check the file format dropdown in the dialog to add 3D parts), and while it still needs mesh representation for most of its functions you can still retessellate on the fly as long as you don't change the geometry. So, you don't necessarily need to export to mesh out of Fusion.
(Also, I strongly recommend not using STL anymore. It is old and inferior to many more modern formats like, preferrably, 3MF, and can cause unnecessary hassle. For example, whenever the triangle list from STL is loaded, the logical connection between triangles is guessed and regenerated by the software as STL does not store that information.)
I'm not sure what you mean with holes. Let's ignore draining holes needed for additive. Is this a hole in the sense of a ring donut with no lattice inside? Or is it a hole where a cavity is connected to the outside and the cavity is meant to be filled with a lattice? Please clarify.
Finally, please keep in mind that Netfabb is not a design tool, and is not meant to be. So, the tools to create or edit defined shape features are very limited.
Kind regards,
Steffen
