Hey!
I’m working on a ring where I’m attempting to bend a group of extrusions around a ring. I’ve done this before and it worked fine, but now when I try and do it the solid extrusions become hollow.
Authenticity Draft.3dm (9.0 MB)
Here’s the file. I’ve tried using flowalongcrv, flow, and bend but they all seem to be doing the same thing.
Thanks 
Before you sweep your curve to get the ring form make sure it is a closed curve. Right now it is an open curve, which will result in an open surface:
I’d just remate that curve with _Rectangle in the Right view using the old curve corner points. Sweeping that new rectangle along your ring curve gives you a closed polysurface of which you can fillet the edges. This will still have you the closed polysurface you’re looking for. Flowing along surface of that will work just fine.
Hey!
Thanks for the help but the issue is actually the polysurfaces themselves after flowing along surface. They become hollow so they can’t be used for a boolean difference. You can see in the photo here that its just two sufaces as an outline of the original polysurface:
This happens if I bend the curve or use flow as well.
The curves from which you created your extrusions need some cleaning up: there are a couple of open curves you don’t need, and _ExtrudeCrv will tell you that there is a self intersection. After cleaning up the open curves you’ll find one with _IntersectSelf. You can fix it by removing the tiny bit and then using _Move to ensure the curve start and end are exactly on top of each other. Once you’ve ensured all curves are closed you’ll get good extrusions.
Now, once you’ve flowed these along the ring surface you’ll find that by selecting these morphed objects are all closed solid polysurfaces. So in theory they are good. I think that the details are just so small that the render mesh settings are not good enough to get the surfaces drawn properly. The settings below appear to show them better
_BooleanDifference still fails for me with the cleaned up bits, but I think that with pouring more attention to ensuring your curves are good before you extrude will likely take care of the problems. For instance this section as shown in below screenshot here has many curve points close to each other resulting in unnecessarily complex extrusions, exactly at the point where the surface intersections failed. I believe that if you clean up the curves, make them as simple as possible (meaning with as few control points as possible) you’ll end up with much better results.
The control point setup of the curve results in unnecessarily complex extrusion:
1 Like
Oh my god I never knew you could increase the NURBs render detail!!! I have always had it set to jagged and fast no wonder I always can’t figure out why stuff won’t boolean. Thank you so much you have literally saved me dozens of hours of frustration :DDDDD