Answered
repeating pattern in outline view
my question is why in preview mode I see this (correct) pattern (a 45° line)

....and in the outline view I see this (unwanted) effect ?

my question is why in preview mode I see this (correct) pattern (a 45° line)

....and in the outline view I see this (unwanted) effect ?

THis does not look like a pattern, it's a repeat, right? ANd then you used a clipping mask?
In outline view you see everything that you have clipped with the mask. Better make a real pattern.
Already have an account? Login
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.