Is there a way to Merge Faces?

[Anonymous]

Occasionally I may get an STL file that has no original source file and I will convert the mesh to a body so I can modify it.  If the object is simple and has several faces on the same plane is there a way to merge these faces so I can bring the body closer to it's original state?  I see something similar happens if I grab all of the faces on one side and use the Push/Pull tool.  They automatically merge together.  However I don't see a way to do this directly.

I've attached an image example.

[Anonymous · Accepted solution]

If you convert STL Mesh to BRep, then you could Merge/Stitch faces in Patch mode.

[Anonymous]

Didn't think to look under patch.  This is powerful and will help me a lot.  Thanks!!

[Anonymous]

@Anonymousis there a reason the Merge command is not available on body that did not start as a mesh?  I split the face of a body at one point.  For some reason it won't allow me to undo that change in the timeline. I would have though the Merge command would be available to stitch them back together.

[Anonymous · Accepted solution]

I do not know what is the reason, but this command (Merge) appears only in "Not capturing design history" mode. But if you split a face you can "merge" them back just by deleting one of them. The remaining will extend to deleted place.

[Anonymous]

Not capturing history is the issue.  Tried on a different model and it showed the merge.

I'll try deleting the face to see if it fills the gap.  Thanks!

[SGoldthwaite]

Is there a way to automatically merge all co-planer faces?  When importing an STL, there can be a lot of faces and doing it by hand isn't practical.

[ereeclimb]

I don't know of any. it would be very powerful if there was.

[HughesTooling]

---

@SGoldthwaite wrote:

Is there a way to automatically merge all co-planer faces?  When importing an STL, there can be a lot of faces and doing it by hand isn't practical.

---

If you use the Merge feature and enable Select Chain it should merge all coplanar faces. Not sure it 100% reliable but works quite well, it actually merges faces not connected to the one selected.

Mark

[Coras_Alin]

Man , you are great, thank you !

[TrademarkCreative]

Just want to say that the 'Merge' tool will sometime not make planar surfaces. 
For instance, if you import something from Blender, which in Blender has a bunch of planar quads, it comes into Fusion as a ton of triangles. 
Then, if you 'Merge' these triangle on the planes that were flat in Blender, you get super small curves. These show up best in the Curve Comb Analysis. 
Thus, if you want to do anything else with your surface, like make a sketch on it, then 'Merge' can ruin that plan for you. 

You can selectively delete faces, but you run the risk of changing the geometry, and it takes forever for complex things. 

 

[TrippyLighting]

Can you share the original Blender file (zip and attach to next post)?

[TrademarkCreative]

Here are the Blender files, and the STL exported from Blender.
And here are the last steps and settings I do in blender

LAST STEP - Planar again for good measure

In Edit mode

A (select all) -> Mesh -> Clean Up -> Make Planar Faces

Factor : 1

Iterations : 200 

ACTUAL LAST STEP

Export from Blender

STL 

No check Ascii

Batch mode off

No includes

Scale : 1

No check scene unit

Forward : y Forward

Up : Z up

Geometry : no check apply mods

[TrippyLighting]

Your Blender model does not consist purely of quads, but plenty of N-Gons! That naturally results in triangles when exported/imported.

I'd actually not use .stl but the .obj format as the export/import format into Fusion 360.

When in Fusion 360 in a new design (with the timeline enabled!), import the mesh though the "Insert-Import Mesh" dialogue.

Create a base feature and then, while in the base feature, convert the mesh to a BRep.

Then finish the base feature.

Now you can start to select faces and hit the delete button. Faces that are coplanar enough within a certain tolerance will merge into a single face. It takes a bit of trial and error to go through this model with success. 

[TrademarkCreative]

Thanks for taking a look. 
Yes I built the Blender to have as many n-gons as possible. 

It is a really bummer that these don't port into Fusion and one must carefully delete the triangles to recover the n-gons.  I've had a small amount of success by also running a Zebra Analysis (Repeats 100, Opacity 20, Lock Stripes) which sort-of tells you which faces are coplanar with each other... but it's not a great solution.

Sometimes deleting faces changes the geometry slightly, which can be a deal breaker.

I've started another thread about this on the API & Scripts threads. Maybe some one will take on the challenge to write a scripts to do some of this work automatically. 
https://forums.autodesk.com/t5/fusion-360-api-and-scripts/detect-coplanar-faces/td-p/10376678

But...I'm at the point where I feel like importing things into Fusion from Blender is a lost cause, for engineering, and should only be used for loose aesthetic purposes.