Imported Mesh and fusion object won't combine for 3D-print

[Anonymous]

After 3 hours of working with Fusion (and the online docs) and failing to find a solution, maybe someone can give a hint here.

I had some experience with 3D construction for visualization purposes, couple of years ago. Now I stepped into the field again for 3D printing, and after evaluating several options, I found fusion-360 to be the most intuitive and thought-through one.

But the current problem really makes me loose my faith.

All that needs to be done is combine an object in STL format (from thingiverse) with parts constructed in fusion.

The import of the STL mesh works fine, and if I turn, scale and output to STL again, fine too (and print nicely after preparing them with Cura).

The objects that I constructed in fusion can also be exported to STL and print fine.

So I move, rotated and scaled them so they fit nicely to the mesh objected that I imported.

Looks perfectly on screen.

But exporting them together as STL (File > 3D print) just does not work.

In the browser both parts are listed unter 'bodies' and can be selected there.

But then the '3D print' functions only allows to select one at a time. Why?

Ok, so the internal representation may be different and the mesh wants to be converted to some 'real' fusion object.

First I tried Mesh>right-click>Edit and then 'Make closed Mesh'. This has some effect on the screen, it now looks a bit more like one object, so to speak. But not for the 3D-print function > same failure as above.

Next try, let's use the mesh to form a fusion-supported object, after several trials (and deprecated hints in the docs) I finnaly found:

Create>Form >> Utilities>Convert

This gives you a dialog box 'Quad mesh to T-Splines' > OK

BUT, the functions aborts because "this body contains a high percentages of triangles" (actually 100 percent)

The triangles didn't hinder it to be scaled, output, printed, so what am I getting wrong?

Screenshot:
https://snag.gy/aHkCVL.jpg

[kate.raskauskas · Accepted solution]

Hi @Anonymous,

Fusion requires both bodies to be the same type in order to combine them, so you can either convert the STL to a BRep (solid) body or convert the body you made in Fusion to a mesh. If your STL has too many triangles, you would need to use ReMake or another program that supports quad meshes to convert the mesh to an OBJ quad file type. What will be easier for your use case is to convert the Fusion body to a mesh, then combine the mesh bodies:

1. Click on the gear in the lower right corner of Fusion 360 and select "Do not capture design history," then click "Continue" on the window that comes up.
2. Go into the Mesh workspace by clicking on "Model" in the upper left corner and selecting "Mesh" from the dropdown.
3. Once in the Mesh workspace, use the Create > BRep to Mesh tool to convert the Fusion body to a mesh body. 
4. Use the Modify > Merge Bodies tool to combine the two mesh bodies.

Let me know if you need any help with that workflow! Once they're combined, you can save that new body as an STL.

[Anonymous]

Thanks, Kate, interesting to learn that it works this way around, too.

I prefer to edit the part that I designed in fusion with its parameters, so I was searching for a way to bring the mesh into this world.

After this thread was closed for some time, I opened a new one with a more focused question:

https://forums.autodesk.com/t5/fusion-360-design-validate/using-stl-mesh-in-fusion/m-p/7370227/highl...

And after some research in the forum, a solution was found by a) reducing the mesh complexity, then b) converting it to BRep.

As a side remark, it might be helpful for some users to be informed about this:

'Fusion requires both bodies to be the same type in order to combine them'

For example, just show a popup with this sentence after importing a mesh.

Would have spared me a couple of hours (not saying that I consider them 'lost').

[TrippyLighting]

The problem is not Fusion 360 but your lack of knowledge.

You cannot combine solid bodies in Fusion 360 with Mesh data. Those represent different and not directly compatible data types.

As you want to 3D print the end result I would actually only export the solid bodies from Fusion 360 as a .stl mesh and then combine it with the Vader mask in Meshmixer.

Fusion 360 is not the right software for this application.

[etfrench]

In addition to what @TrippyLighting says.  You can import the exported Fusion 360 stl file back into Fusion 360, then create a new stl file with both the thingiverse stl and the Fusion 360 stl. 

[Anonymous]

"The problem is not Fusion 360 but your lack of knowledge.

You cannot combine solid bodies in Fusion 360 with Mesh data."

Yes, so I tried to compensate lack of knowledge with reading the docs and communicating.

Like all software users do it all the time around the world.

And it was successful 🙂

And my proposal was to bring this simple fact - that mesh and solid bodies constitute two different types of data in Fusion - should be brought closer to the user.

Because it would be desirable to have more people learn this quicker, would it?

About the proposed workflows - why should one use a) another software or b) several import-export steps if it can all be done inside Fusion with one step?

Don't tell me you didn't know that it was that simple (once one grasps the 'Capture design history' switch, which is .. a bit counter-intuitive)...

[TrippyLighting]

Well... one reason to use another software is of course to educate yourself 😉 Knowing now how to do that in Fusion 360 in this particular case, gets you an end result but it does not do anything to further your knowledge what the difference between a solid and a mesh is.

Another reason is of course to use a better tool for a given task. 

Meshmixer is simply a much better application if you want to work with triangulated meshes and most of the tools in Fusion 360's mesh workspace have better equivalents in Meshmixer.

Fusion 360's nature is to be a CAD application and the desired end result is a Solid Body / BRep.

Yes, you can export that into .stl as a final end result but using that triangulated mesh stuff in a CAD application is really not a good idea, unless the purpose is to reverse engineer geometry based on such a mesh. But even for the Fusion 360 is not a good application that can do this efficiently and precisely. The purpose of CAD is accuracy and you cannot get that from a triangulated mesh.

[laughingcreek]

Everything @TrippyLighting is telling you is spot on.

Yes, fusion has some mesh handling capabilities.  But they are not very robust, and you can't count on being able to complete a mesh project every time.  And certainly not one of any size.  If 3d printing and related mesh manipulation is something your going to do very much of, you need to learn some more software.  I'm a fan of MeshMixer for many of these tasks, there are others.  

[Anonymous]

I'd prefer to handle all parts of a construction with parameters, splines etc.

Meshes are obviously cumbersome and tedious to work with.

The only reason to use them is that numerous third-party 3D parts are available only in mesh format;

maybe because no file format for parametric models has been established as a (be it practical) standard, yet.

Yes, it would be nice to approximate a spline-based or parametric object to the mesh more flexible in Fusion.

Meshmixer does not help with this either, AFAIK.

[TrippyLighting]

---

@Anonymous wrote:

Meshes are obviously cumbersome and tedious to work with.

---

This applies to triangulated meshes. Quad meshes are easier to handle and can be converted into a T-Splines.

[laughingcreek]

I over looked this part of your original post-

"But exporting them together as STL (File > 3D print) just does not work.

In the browser both parts are listed unter 'bodies' and can be selected there.

But then the '3D print' functions only allows to select one at a time. Why?"

Don't know why 3d print works that way, not intuitive.

But, you CAN export all of your bodies into a single stl file.  this is done at the component level. (still not intuitive.)  If you want to export all of your bodies, then you can right click on the first thing in your object browser (it will have a cube icon indicating it is a component, and the name of your file.) and select save as STL.

If you don't want to export every thing, then you can put the bodies you do want to export in a component, and right click the component and "save as stl" 

[Anonymous]

Ok, this has been explained by Kate, if you want to export something in one STL file it has to be combined first, just aligning the parts on screen does not suffice.

And this can only be done if the parts have the same 'type', which is either some-non-mesh-object or mesh.

So one has to convert his some-xx to mesh first, or vice versa.

Basically, one might expect to get out of any 3D software what he saw on screen.

So, if there are any plans to make the software more intuitive, this could be one field.

[Anonymous]

"you CAN export all of your bodies into a single stl file.  this is done at the component level. ... If you want to export all of your bodies, then you can right click on the first thing in your object browser (it will have a cube icon indicating it is a component, and the name of your file.) and select save as STL"

Just tested this with a fresh file. Does not work here, only the fusion-object gets exported, not the mesh.

Although both are childs of one component in the browser.

Then again, it works if you (reduce and) convert the mesh-to-BRep before, so what the component-Save does save you is the combine step.

Still, the loss of detail through the mesh-reduction is the main problem (for more complex mesh parts), and that's not different here.