Rectangular pipe bend modelling

You can use freeform tool for this. Just add two or more curves and some points on the bent face and push inwards.
I've done similar task roughly in the attached file.

Make sure you use freeform tool before applying fillet and if you can split the surface for other transitions to the nearby straight faces.

U can make this using swept command in solidworks.
In first step make your sketch using line command and fillet command.
2nd Step draw rectangle on starting point of line.
3rd step use swept command.

Thanks guys. I tried your suggestions but was still having issues coming close.
I got an Idea to use boss extrude with cut and fillet. i then used the shell command. by far its the closest and looks good enough. I hope in the future a single command for this could be added.