Hi 3Dfanatic,

re:
> I kept the lines and main objects that I swept before doing the second action which
> is what is causing the removal of the edge.

What is the second action that you're referring to here, is it using Trim ? If so then when you're cutting a solid it is easier to use boolean difference instead of Trim. Trim operates only on surfaces, while the booleans work on solid volumes and are able to make a solid result automatically joining in the pieces of the extruded cutting curve. You can get the same result with Trim but it's more work because you'd need to extrude the curve into a surface and then trim that surface and join the results together. Booleans basically do all that work for you.

So for your case here with your solid you made from your sweep, select the solid and run Construct > Boolean > Difference, and then select your curve as the cutting object:



That will divide it into 2 solid pieces:



Delete the pieces you don't want and you'll be left with a full solid and won't have to worry about closing up holes as you would if you work only at the surface level with Trim:



One thing to note is that although it works ok for your case here, it's generally not good to have your cutting curve overlap right over top of other areas of the model like in this region here:



That can tend to complicate booleans because it's going to extrude out a cutting surface from that curve and the extrusion is going to be skimming right along the same surface area of your main shape and it's more difficult to get a clean intersection curve from stuff like that. In order to do booleans, a well formed closed intersection loop of curves have to be generated to divide the object up into different clean pieces. If the intersection curves are complex and criss-cross over each other that might not happen.

So instead if possible it's better to have a cutting curve like this where it shoots out a ways instead of having spots that hug right along the same shape:



Then for filleting, the problem there is your shape is very thin and so there isn't much room to fit fillets in, about the maximum size that will fit is around 0.01 units, if you try to use a radius much larger than that it would cause the fillets to collide into each other and cause the type of artifacting that you're describing.

So use a fillet radius of 0.01 or smaller for your particular case here, here's an example of what it looks like with 0.01 :


Hope that helps!

- Michael