close the top of my object

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 From:  Finema
7102.1 
Hi,
I'm sorry but idon't find how to close the top of my objet.
I join a screenshot and my .3dm.
What's the process ?
Thanks.



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 From:  BurrMan
7102.2 In reply to 7102.1 
one way:

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 From:  Michael Gibson
7102.3 In reply to 7102.1 
Hi Finema, the way Burr shows by making a 2D profile curve and then extruding that and trimming the result is one good way.

Another possibility is to get the top edge split into 2 pieces and then loft between them. But that makes a surface that is pinched down to a single point on the start and end, the extruded surface is of better quality.

Another way that can be good to form caps like this is to initially construct an object that is slightly extended and simplified at the top with a regular planar end to it, and then cut off that end with the 2D profile curve by using boolean difference, that will leave the extruded imprint of the 2D profile curve with fewer steps needing to be done.

That looks something like this:

Initial shape is extended and ends at a simple top plane instead of constructed to a 3D waving curve:



Select the base solid and run Construct > Boolean > Difference and use the 2D side profile as the cutting curve. It will slice the solid into 2 pieces leaving the imprint of the 2D curve:


Delete the piece you don't want:



Often times it can be easier to construct shapes to simplified boundaries like that to make a base solid that has some extended areas in it, and then use boolean difference to cut away the parts you don't want, rather than trying to directly construct the shape to an irregular boundary right from the start.

That tends to save some time when you're able to work with solids and 2D profiles more throughout the process.

- Michael

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 From:  BurrMan
7102.4 In reply to 7102.3 
Hi Michael,

""""""""""""But that makes a surface that is pinched down to a single point on the start and end"""""""""""""""

Yes, I avoid those like the plague. They seem to always cause issues for me further down the road.. Is there anything that can be looked at for the loft to add functionality here? Something like added drag points (I don't know what you call those. There exists one set on the blend and loft type tools already) Maybe it would be similar to "planar sections" and "add sync points" that are in blend? Something that would avoid that type of poling in this particular type case....
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 From:  Michael Gibson
7102.5 In reply to 7102.4 
Hi Burr well I don't know how Loft could construct a surface without poles in a case like that, you have to use an extended and then trimmed surface like you did to avoid poles.

The drag points are for the case of lofting or blending between closed curves, where you can control where the seam edge of the closed surface will be at. It can't really apply for the one single closed curve case though.

- Michael
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 From:  Finema
7102.6 
Thanks a lot Burma and Michael.
I've tested the twice and in my case, the boolean way is the fastest solution.
Thanks again !!!
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