Surface Trimming

Hi everyone; I’m new either to Rhino and forum. My question is I want to create a rectangular surface and a quarter circular surface intersects the first rectangular one. To achieve this I just used the “control point curve” command and draw four linear edges which made a rectangular; then I used “Surface from 2,3 or 4 edge curves” to make a rectangular surface. Then I draw a quarter arc inside the rectangle and then used “trim” command, first selected the arc as cutting object and then selected the rectangle for the object to trim. It seems it works for the visualization but what I really want is I want to add the quarter circle’s control points are embedded into the rectangle’s one. How could I achieve this ?

Hi kahasim- can you post your objects? My guess is you may want to Revolve a line 90 degrees to get what you are after.