Hi Branden,
> However, I'm not sure how you did the subsequent trim and sweep to fill
> in that triangular patch. Can you elaborate on those two steps a little?
There were a few kind of tricky steps along the way there.
First of all when doing the surface/surface fillet generation it will try to trim the surfaces but in this case makes a bad trim, so you only want to keep the fillet and not any modification to the surface. You do that by selecting the fillet, doing Ctrl+c to copy it to the clipboard, and then undo to restore things to their previous state, then do a paste. You can use this sequence "copy, undo, paste" anytime you want to preserve just one piece of a generated result but not any other modifications that happened.
After doing that on both fillets, you now have 2 fillet surfaces, one of which extends a ways past the other. You need to trim the longer one so that it ends at the same spot. This is done by selecting it and using the Trim command, with the Isocurve option. That allows you to pick one of the surface's own U or V directions as the cutting location, this works well for cutting fillets since one of those directions is the rounded direction. Snap the isocurve cutting location onto the spot where the fillet edges intersect with one another, and discard the excess end. Now you have the fillet surfaces all set up, the remaining thing is to trim a hole in the main object to make room for them.
The tricky part about the trim is that you have to cook up some kind of shape from the converging point onto the ends of the fillet. I decided to use curve blending to do this - in order to do curve blending between the edges of the fillet and the edge that ends on the converging point, you need to duplicate the edges to have regular curve objects, because if you try to run blend on edges it will generate a surface/surface blend. Curve blends are only generated between 2 "standalone" curves, not between 2 edges. So I duplicated the edges into regular curves by selecting them and doing copy / paste. Then I selected the ends of those curves and did Construct > Blend to make a smooth blend between them. Then switched to the top view and grabbed a corner of the edit frame and squished them down to be planar with "flat snap". Then used Construct > Curve > Project to project those now-planarized curves onto the surface to be cut. With that done that now fills in the empty space so that there is now a boundary that runs across the entire area so it can now be trimmed to that boundary.
So quite a lot of stuff going on there, let me know if you are stuck at any of these steps and I can explain that one in more detail yet.
- Michael
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