Any way to export the file as a 3d body and not a mesh?

Ok, so i have fusion 360 full version installed so i can do FEM/FEA analysis on my parts i create in sketchup, the only issue is… FEM/FEA has to be done on a solid body. Any time i use the advacned feature to try and convert the stl file to a solid body in fusion 360, it always errors out. Is there any way to somehow have sketchup export as step or some other solid type body rather than a mesh?

Or any type of FEA software that will accept a mesh file and show me all the important things like node count, etc etc?


EDIT: if i have to do a mesh, whats the best way to export the file? OBJ? STL?

There is an extension called Solid inspector

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i use that all the time:) love that extension. Sketchup still saves and exports as meshes, even if they are “solid” but what i need is a solid body type file. or at east not a mesh taht is so messy

Meshes are difficult to work with, drives me crazy

I don’t understand what are you asking. Is your model a solid entity? sometime solid inspector says it’s a solid but on the entity info tray it doesn’t say solid group or solid component. Can you share the file to check if you have a solid entity?

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well the true question is, what file format do you export from sketchup.

because if a shape is a solid in sketchup, then it is a solid. in sketchup. but depending on what file format you export to, some might only export faces or vertices.

Exporting from Sketchup (to most 3 file formats) will likely triangulate your faces. That’s how it works, the only way to ensure a face is to make it a triangle. Since converting could result in micro movement of points, softwares like to triangulate

So in the end, you’ll have some clean up work to do in fusion. but depending on the format you use, you might have more or less cleanup to do


I have not tried it for a long time, but I seem to remember that exporting SketchUp Solid groups or components to DWG (3D export) used to make ACIS solids out of them. The formats mentioned (STL, OBJ) are mesh formats so any “solid” information vanishes when exported to them.


In cad modeling solid means multiple things. Solid in SketchUp means water tight, in any other modeling system, solid means its a solid body (think of clay) not a surface mesh. Sketchup is a paper modeler in the sense that its like origami while fusion 360 is like molding clay

I think the issue is that step files, according to my research last night are nurbs files and SketchUp doesnt deal with nurbs.

I have the paid version of 360 and it even struggles with converting meshes to solid bodies.

It may be a solid in SketchUp but its not a solid body. Thats the issue. SketchUp is a paper modeler kind of like origami. SketchUp is a surface modeler and fusion is a solid modeler… that’s where the disconnect is for my project.

This ia why i am looking for a better way to export the file, one that doesnt triangulate the faces or at least as much.

Quad faces might be better than triangles but i dont know how to do that in SketchUp

Ill have to look, but i thought dwg was a flat 2d model even though its under 3d… maybe im thinking of dxf?

Your info is KIND of right… but also KIND of wrong. Solid vs surface modeling is a function of how a 3D model is created… interchage formats like STL or OBJ contain different information, but the geometry is prety basic… it consist of points in 3D space and data about how they are connected. If an STL file for example is imported into a solid modelr, the software will choose to see the 3D gromtey as a solid when it imports… a surface modeler will choose to see a series of interconnected surfaces in 3D space. an STL file has no iuse of what is a solid, it is just dumb data.

For example, I export stl solids from SketchUp all the time and have no problem with them being interpreted as solids on the other end.

If your FEM/FEA software needs something specific, it is important to find out what is needed. All files exported from SketchUp will include basic geometry (sprinkled with additional data, depending on which format you are working with).

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It gets tricky trying to go from one software to another haha

Fusion 360s fem needs a solid body, and fusion uses nurbs for their solids since they are a parametric modeling system.

My issue is that when SketchUp exports as stl or obj, sometimes the mesh is not exported correctly even though the solid inspector says the part is solid because when i import it into fusion 360, there are some added faces that i can see that are not on the part in SketchUp.

So i need a better way of exporting the part from SketchUp so i can convert it to a solid body (not solid surface) that fusion 360 needs for fem.

Fusion can handle solid surfaces and solid bodies, and so can solid works but SW is expensive haha.

So im trying to find the best way to export from SketchUp so i can import into fusion to convert to solid body :slight_smile:

Im going to ask the fusion forums as well. I think this is excellent information for all of us to share.

To solve all my problems, someone needs to make an fem extension for SketchUp haha

it is solid, it has volume and entity pane shows solid. I personally think its the way SU exports the stl or obj file, but i could be wrong

It can be tricky, indeed! I usually recommend that, when exporting, users try to find out exactly what the other program is expecting, then find the interdeiary file that most closely aligns with that, and go from there. there is no way to make SketchUp handle it’s own data differently, and there is no way to force it to export data other than what it already does. Given that, the next step is to see if any of the emportable file formats work to import geometry into your engine.

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yeah, F360 needs that step file format. So sadly i have to convert the mesh to a step file in F360. this is where the issue is happening. F360 is having a hard time converting the mesh. Su reports solid and a positive volume of my part BUT f360 and freecad both say the part is not solid and has no volume due to some holes in the part… The only way holes could have happened was during the exportation process to STL.

What thoughts do you have on that part of exporting? SU reports solid and has volume in the entity pane, but after exporting, it has holes in the mesh.

Personally, i think SU could benifit from exporting to step file format. It does not require parametric or nurbs… i dont think.

The STEP File Format – Simply Explained | All3DP

There are a few extensions that do export to step. One of those might be worth checking out.

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which ones in the extension warehouse are you thinking of? i only find one by simlabs but its for importing?


Oops! Yeah… I was thinking of the importer… unfortunately, I do not think anyone has made a direct exporter for step files… I think it has something to do with step storing nurbs info, which SketchUp does not do.

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Have you considdered that it might be the other way round?
When I export a solid as .STL and open that in Cura I never get extra faces…
So it seems to me there is something wrong with the Fusion360 importer, not SketchUp’s exporter…

Maybe not the answer you want to hear, but why don’t you model the whole thing in Fusion360??

Good point of view and perspective. Ill have to test it out. Its been a while since this post, but i THINK, dont quote me on this, but I think prusa slicer showed extra faces… Ill check though

SketchUp is far easier to model in. I used to exclusively use solidworks but after a couple of years, it just bugged me. Su is just faster, dont have to worry about the sketch planes etc etc.

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I completely agree, but with all these file conversion troubles it might be faster to model in Fusion360…