problem using boundary fill to split mold

[charlieuk]

I have been following lars's video on creating a mold unsinging surfaces created in the patch environment (which was a first for me) and then going back to model and doing boundary fill however I cant seam to get it to split into to parts. im assuming there is a error some were in the surfaces but not really to sure were im going wrong or if there is another way to split the mold using the surfaces I have made.

If anyone could take a look and give me some tips I would be much appreciated!  

https://a360.co/2TQhoaN

many thanks

[davebYYPCU]

Had to wonder how a boundary fill (creating a solid) could actually split a mould.

It appears that there are bounding surface bodies, around the wing, if they are stitched together to become one body, I presume you can use it to cut the wing.

Might help....

[charlieuk]

thanks for the reply like you say it seams odd but I was just following this https://youtu.be/fRS0ZeXabaY?t=1664

[davebYYPCU]

Didn't watch it all, but I take it you are needing to make the mould, not split the wing.

Surfaces you have would now need the mould material, and I didn't see them, (not visible or to be made?)

so yes to make the solid half mould, the Boundary Fill makes total sense.

So where is it you have a problem?

[charlieuk]

yes it is the mold that I am trying to draw.

in the video lars creates a block from which he subtracts the part from the center to make a cavity. he then uses boundary fill and the surfaces he has drawn around the part to split the mold in two( although the video actually ends before this) 

I have had it kinda work on a very basic test but could only get it to create one half of the mold however on the wing I cant get it to work at all. 

I have drawn the block subtracted the part then created the surfaces I want to use as the parting line but then cant get it to split with boundary fill like in my test or in lars's video. 

many thanks

[TrippyLighting]

I've attached the wing model and was able to create an upper and lower mold half. However, it's not exactly straight forward. The problem is the trailing edge which is not sharp but a ~0.2mm flat area.

I used that flat area to first split the mold vertically.

Then I created a 0mm offset from the 2 top surfaces, stitched it together with part of the outer rim and ...,

Well, just go through the timeline and see if you can make sense of it and come back if you have questions.

[charlieuk]

cheers thanks for that I have managed to recreate that method which is great and I can carry on with this project so much appreciated. 

In the quest of learning more I would still quite like to know what I was doing wrong with boundary fill if anyone can help there. 

many thanks

[TrippyLighting]

This is a borderline case where boundary fill does not work.There is nothing you necessarily did wrong.

What I would recommend is to make sure that the curvature of your splines is clean and smooth.

That's not the case in your current model as the splines have too many control points.

Curvature problems often can throw tools in Fusion 360 for a loop.

[charlieuk]

ok that interesting, I was struggling trying to make a parting line down the center of the trailing edge which is why I ended up with the ugly spline so maybe I need to come up with a better way to do that.

[TrippyLighting · Accepted solution]

A better way to create that particular spline is a CV spline as that is easier to control in this case.

While that still take a bit of fiddling I was able to create one with 2 end points and 6 control points that worked.

With that spline I first split that .2mm flat training face. The edge created by that face splitting is what the boundary fill tool needs.
Then In extruded a surface for spitting from it and stitched all the rim surfaces.

Then I was able to use Boundary fill.

[charlieuk]

ok many thanks I have not used cv splines before so ill have a play with that. 

[TrippyLighting]

If you want to accept any of the replies as the solution then we can close this thread.