If someone says, "Your design is too flat". What does it mean?
How are you?

I have talked with my professor few hours ago.

He said when he was at USA, one of his friend was in difficult, because his friend's professor who is PhD advisor said "Your design is too flat".

His major was the science of architecture.

I wonder what is the "flat" mean.

Is it just flat literally?

Thank you for your help in advance.

Question

If someone says, "Your design is too flat". What does it mean?
How are you?

I have talked with my professor few hours ago.

He said when he was at USA, one of his friend was in difficult, because his friend's professor who is PhD advisor said "Your design is too flat".

His major was the science of architecture.

I wonder what is the "flat" mean.

Is it just flat literally?

Thank you for your help in advance.

Answer

He could have meant "flat" literally and perhaps also in the sense of being insufficiently bold or interesting in terms of its aesthetic appeal.

Answer

Flat: lacking interest or emotion; dull and lifeless