i will describe the attached visual in an attempt to explain. there are two arrows on the 'bending' image. one is a hand drawn line arrow (right) and the other is blocky (left).

i can bend as shown by the blocky arrow. however, i do not know where to start with the triangle and therefore i havent received any errors yet. the two sides of the triangle (represented by complete black lines) need to bend 90 degrees around the axis (represented by the fragmented line). i dont know how to cut the two sides of the triangle out of the sheet metal in order to bend this section against the fragmented line.

does this explain? if not let me know where its confusing and ill have another go.

thanks a lot, john