I have done a lot of boards which are rigid in nature. However, my new project requires of a rigid-flex design. I haven't worked on flex boards yet. Can anyone please guide me how to design felxible circuits with Allegro? Any documentation or link would be of great help.
It is very similar to designing a rigid board with a minimum number of layers. For the stackup you use the Cadence soldermask layer for what is called a "coverlay" layer on a flex circuit. You will need to work with your flex fabricator to understand their spacing constraints and capabilities. In between copper layers you will define your adhesive layer thickness requirements. Many flex fabricators have good general design information on their websites.