The Fill.1 element with element Fill.2 is cut off in the picture below. The system according to the settings leaves the part of the surface to which the mouse is clicked (in this case the right part of the surface). If you want to save the opposite part of the surface, you can change it by clicking on
Trim is an operation by which two elements are cut off interchangeably. With the Trim operation, it is possible to cut off the curve with the curve or surface with the surface interchangeably. It is necessary to select the elements we want to cut (they appear within the Trimmed elements field). The system here also retains the part of the elements where we clicked the mouse. If we want to change the result, click on the Other side / next element and Other side / previous element. With complex geometry, it is possible to select elements that we want to remove or keep (Elements to remove and Elements to keep). And here it is possible to get an intersection between the surfaces, by including the Intersections computation option.