Can anyone help me figure out why when I open a drawing that I have been working on, the drawing is OK until I go to orbit or any other comand. Then I get these weird triangle shapes on my walls and roof. They are on my int/ext wall layers. when I delete the triangles my walls disappear. This is fine with me but when I draw the walls back in, the triangles come back. What made them appear and how do I KILL THEM. I have tried everything and they are driving me nuts.I have drawn the walls as a plan view and then raised them to the correct hight so I am sure that there are no extra lines and they are square. Can anyone help. Please I really need to complete this drawing soon. Thanks