Although I downloaded Sketchup some time ago I only started using it recently and have been drawing an arrangement of teller’s counter which is t be installed on the project I am currently working on. Today for no apparent reason, well not to me I started getting strange happenings when I started drawing this morning. For example; when I draw a line a series of squares or diamonds appear of red or other axis colours. If I press ESC and move the drawing tool, then I get a fan-like set of black lines. I have attached a prtsc as a .jpeg file to show more precisely what happened.
Can anybody throw any light on this phenomenon? I have put quite a number of hours into this model and would hate not to be able to bring it to a conclusion.
It looks like graphics card issues. You could try updating the drivers. If you are really using SU8 as your profile and screenshot indicates you can also go to Window>Preferences>OpenGL and disable Hardware Acceleration to see if that helps.