Need help on creating loft with several undercuts

[infoQN65E]

Hi all,

I'm desperately trying to create a flexible tube-like loft element, which is supposed to be printed via FDM or SLS printing. I already had succesful outcomes but the construction was way to complex that I had to make it a little easier this time.

The problem I'm facing this time is that the volume cannot be made as a Shell. I had to cut the lofted volume into several pieces and made chamfers and fillets on all edges to get a little conformity into the undercuts

After combining them again, the Body won't Shell anymore.

I already tried to design it via sculpting mode but didn't manage to combine the sculpted object with preconstruted objects, that were modelled with Sketches. Sculpting it made it furthermore less predictable  and last very Long as well, which made it not usable for me.

Does anyone has a clue how to do it in a more elegant way or to construct it in a way that is possible to create a Shell afterwards? 

Really looking forward to any advices you could give!

https://a360.co/2LoOXww

Flex

[TrippyLighting · Accepted solution]

That's not much of a surprise as the quality of the geometry you created is pretty bad.

Starting with some of the imported )or so I asme - curves that are less than smooth as can be seen in the screenshot. Those alone, however, are not the problem

The problem is really your use of the chamfer tool (Fase in Deutsch). Due to the curved and lofted nature of this object this breaks these chamber surfaces into hundreds of small surface patches of which many contain near-tangent conditions, which is why the model fails to filet.

[infoQN65E]

Thanks a lot for this hint. I didn't checked it in a while and since I've copied it from another construction I didn't even think about checking it at all.

That really improved the performance handling with it even with the chamfers. The surfaces aren't separated this much anymore but I still can't shell the volume. 

What irritates me the most is, that I can shell a comparable version of this that has parallel top and bottom planes(and a slightly different bottom cross section).

Any idea about this?

[infoQN65E]

Just a Little update:

solved the problem by enlarging the height of the transition between the flexible chamfered part and the top. It was just not enough space to get the desired width. 

Thanks anyway!