Converting Blended Surfaces To Solids in Fusion 360?

[Anonymous]

Hi, 

I have a kite geometry of two surfaces that I have joined together and stitched using Fusion 360 PATCH section. I now have converted this to a solid body successfully, although the resulting body has bad geometry at the trailing edge. 

It is an airfoil type geometry. 

How can I fillet this either once solid, or at the surface stage? I have tried filleting the solid but it does not work, and can't select the edges in surface mode. 😕 I am stumped. .It is needing a smooth edge for meshing purposes. 

Any help greatly appreciated on this! 

Adam

[jeff_strater]

Hi @Anonymous,

Can you share your design here, and maybe a screencast of what you are trying to do?  It's not really clear what the problem is that you are running into.  Airfoils can definitely be a challenge.  Depending on what you want to do, you can either Stitch together surfaces to form a solid, or use Thicken to create the solid.  You can fillet in Patch mode, if the surfaces have been stitched together.

Jeff

[Anonymous]

Hi, 

When I open the geometry currently in ANSYS I see this appear:

 

I had tried to thicken each of the surfaces in Autodesk Fusion and inventor to achieve an object that would allow me to mesh it appropriately. Unfortunately I think maybe because of the sheer edges and small gaps it just wasn't liking it. So I have attempted to create a solid to avoid this problem. 

This is the geometry: 

[Anonymous]

Apologies I have added my comments to each picture, 

[Anonymous]

In the first photo it shows leading edge and trailing edge, with circles enclosing the patched regions. The second photo shows me now trying to fillet this solid body. I don't need it to be this feature, as I guess it needs something else.But I need to smooth this sharp trailing edge 

[TrippyLighting]

If it's a solid you should be able to fillet the trailing edge. Instead of pulling with the arrow in the viewport, type a fillet radius into the file for it. 

On such a sharp edge I'd start with an 0.1mm radius.

[Anonymous]

Strangely it only accepts that the two bottom surfaces are allowed edges to be filleted, and even these I cannot apply filletss to: 

[TrippyLighting]

You may want to change your default units from m to mm.

The fillet UI dialogue shows 1 m for the fillet radius. Not sure what the overall dimensions of your designs are but 1M for a fillet radius seems very large to me.

[Anonymous]

I wish it were so.. I tried with any number of 0.000000001m and still no effect. I wonder whether it may be due to the fact that even though I have patched and filled it there is still no thickness to the surfaces at the edges.. therefore maybe that is the issue? I am not sure..

[TrippyLighting]

In that case, please share your design (export as .f3d) . If this is imported geometry from another CAD package there is a chance that the edges are problematic, but a quick check with the curvature plot can clarify.

[Anonymous]

I have attached below

[TrippyLighting]

That is certainly very curious. I don't even seem to be able to select that trailing edge.

The curvature plot does not look smooth but I am not sure if that's the problem.

@jeff_strater would you be able to look at this ?

[jeff_strater]

Yes, I can take a look.  It's very strange, all right.  You cannot even select that sharp edge to try to fillet it.  Usually, the only reason why edges are blocked from selection in Fillet is if it is a "tangent edge", meaning the faces adjacent to that face are tangent to each other already (which would therefore prevent us from filleting that edge, obviously).  But, that edge is clearly not a tangent edge.  We will have to investigate that.

I suspect that this edge also may be contributing to why you cannot fillet the "base" of the airfoil.  But, I'll have to check on that further.

Jeff

[Anonymous]

Thanks for taking a look. I have tried opening and editing in Inventor, Rhino.. nothing seems to produce any meaningful result.. I am very stuck. 

Adam

[PhilProcarioJr · Accepted solution]

@jeff_strater & @TrippyLighting

If you look at the curvature map and un-stitch the model you can see the surfaces intersect (or at least touch) at the pointed edge. That appears to be the reason why it will not fillet. If you move the surfaces just a little bit then the fillet works.

Edit:

This is actually easy to fix. Trim off the offending edge and unstitch the body. Then overbuild the surfaces and trim, then stitch it all back together.

I will see if I can post a video and the fixed file when I get time.

[PhilProcarioJr]

@Anonymous

Here is your fixed model, keep in mind if you want larger fillets you need to increase the rear fillet size to do it.

[Anonymous]

Just seen your message come in now will take a look at the model! 

[Anonymous]

Thank you so much Phil and everybody for taking the time to help me on this. This is exactly the solution I am looking for! I will definitely need to play around with this trim feature as I kind of see where you are going but haven't played around with the surfaces features that much. 

[PhilProcarioJr]

@Anonymous

Your welcome, trimming and over building surfaces is a must learn work flow. There are so many cases where this is really the only option. Another thing I would point out is when your building things like this in the future keep your base forms simple and refine the shape as you go. A lot of times trying to build your final shape from the start will only back you into a corner. For instance on each end of your airfoil you should have kept them flat until the final steps then cut the angle in them. This would help with the initial shape and would have blocked some of the trouble you were having. It would really help to see how you built this in the first place, then we could help you to model in a less problematic way. We are here to help so don't hesitate to ask when you have problems and someone will help.

Cheers

Phil

[Anonymous]

Thanks Phil, I was provided the file as attached, with only the two large surfaces. 

I soon realised that to mesh this within ANSYS AIM I would need to create a solid body from these surfaces. 

Initially I attempted to thicken the surfaces to create an accurate hollow like structure, but unfortunately I think collision occured between the two thicknesses, or the sharp angles produced poor meshing in ANSYS AIM, so I tried to simplify this by closing off the edges. 

Unfortunately it still produced "bad faces" at the fillets now when I attempt to mesh in ANSYS AIM, so I will attempt to trim and re-fillet I think for a larger more rounded edge as the fillets appear as "bad faces". 

Adam