How to fillet the following shape using a constant fillet radius?

Rhino Rhino for Windows
1

Please guide me step by step.
1.3dm (120.1 KB)

2

Hi Alex - see if the attached helps - the key is to replace the flat surfaces with trimmed planes (ExtractSrf, then Cap). I also included a blow by blow for doing this with FilletSrf for when it’s a little less tractable.
Yes, FilletEdge should work on the surfaces you have, I would say, I’ll get it on the pile.
https://mcneel.myjetbrains.com/youtrack/issue/RH-42634

1_PG_Fillets.3dm (511.4 KB)

-Pascal

3

OK, Thanks.