Fillet surface and edges not working even for simple box

I’m learning rhino and I’m getting frustrated because of this problem. Whenever I fillet or chamfer an edge or surface the remaining object isn’t connected with the filleted edge and I’m also stuck with some weird artifacting.


Hello - if the box is one joined thing - that is, the surfaces on either side of the edge and the end faces are all joined then FilletEdge is the tool here - FilletSrf will not do anything about either the end surfaces nor joining it all back up - FilletSrf is a ‘surface level’ operation that only deals with the two inputs as separate surfaces. FilletEdge attempts to keep joined faces joined.