Just want to know how I would extend a roof about a metre to the one side but only on a section of the length. I dont want to join another roof but just extend it. The lounge comes out a metre on the one side but only for about 3 metres then the rest of the house is a rectangle
A couple of assumptions:
If you are wanting to extend farther down the slope, I'd isolate that section by moving the pieces you want to stretch to an empty layer, then I'd change to a view that looks directly along the facia, (view, elevations, new [if it doesn't match front, side, etc]) and stretch the area farther down the slope. I'd copy the roof polygon temporarily matching the ridge to eave to make a reference line so that the stretch doesn't accitentally change the roof slope.
If you are wanting to extend in the direction of a horizontal ridge, so that a piece of that roof sticks out farther, the new 3d knife is great for that. Copy the roof to a new layer. On that layer, move the entire group (facia, roof, underside, and gable end) farther up the slope to the correct position, and cut off the part that extends above the ridge with the 3d knife. Go to 3dMenus, 3d Entity, Polygon, 3d Knife. It will slice any polygon or group of polygons on a vertical line. Then just mirror the resulting polygons at the ridgeline to get the other side of the roof.
If you don't want lines to show up at the joint between the original roof and the extended portion, use plane snap (3d menus, 3d views, plane snap) and set the roof plan as the working surface. Set z-height to zero, erase the two pieces of roof plane and add one new polygon with the correct shape.