Heinz and Vanessa's relationship

Vanessa is the daughter and only child of Dr. Doofenshmirtz whom he had with Charlene Doofenshmirtz. As badly as he had been abused as a child, Doofenshmirtz cherishes his own daughter dearly and devotes much of himself to trying to make her happy. Vanessa, though mostly unappreciative of this, always understands the trouble her father goes through for her sake in the end.

As a typical teenager, Vanessa is frequently embarrased by her father. She feels his shenanigans are threatening her impression on other people and openly shows it. She has also come to believe that it is on his account her life has been twisted beyond the recognition of that of a normal person. However, she understands how much he strives to make her happy as his daughter and shows recognition for it when he succeeds.

Dr. Doofenshmirtz's Impression of Vanessa
Doofenshmirtz goes to great heights to make his daughter happy.

Vanessa's Impression of Dr. Doofenshmirtz
Vanessa has always displayed dislike towards her father. This was probably at its highest peak during her coming of age.