Hi Anis,

> I use loft because the area is not planar. You can check on my red curve.

I see - but actually the exact same advice I mentioned previously still applies.

Just use the red curve as the cutting object the same way I used the line in my previous example.

Any time you want to make a cut that follows a 2D profile you can use that method - for example here I have exaggerated the curvature just to clarify that the end result does not have to be planar:





Select the solid and run boolean difference, and select the profile curve as the cutting object to get this result:



Just discard the pieces you do not need:



In this case you don't get a plane as the result surface, but the result is similar in that there is no pole. Instead it is an extruded surface (with a line as the cutting curve, it will be a plane since the extrusion of a line is a plane), here are what the control points look like when turned on:




Not only can you avoid getting a surface with a pole with this method, it is generally faster as well - just cap off your base shape so it is a solid, then you can carve off chunks by doing a boolean with a profile curve as shown here.

When you start with a solid, then the boolean cuts will generate solid pieces with the curves leaving extrusions behind to form the caps.

- Michael