# Non-rectilinear core area

Tool: Initialize Floorplan

Subcategory: Floorplan customization

## Conversation

### Blebowski
Hello,

is it possible to somehow specify core-area that is non-rectilinear (e.g. as a group of polygons surrounding concave shape) ?

I understand that if doing "digital on top" FP where all the analog is a digital macro, this does not make sense. However, it may be usefull in case where "analog-on-top" is done, and digital may have some weird shape and is eventually placed as hard GDSII macro into analog-on-top design.



### maliberty
The simplest would be to make a rectangular block and add placement and routing blockages for the disallowed area

### Blebowski
Thanks. Can I then do the `add_pdn_ring` around just the cut area (e.g. L-shape pdn-ring) ?  Or is there some other trick how
to achieve this ?