Pitch
The distance between the center to center of the metal is called as pitch. In the below picture, B is pitch.
Spacing
Spacing is the distance between the edge to edge metal layers. The distance A is spacing in below picture.
![pitch-spacing-vlsi](https://ivlsi.com/wp-content/uploads/2020/10/route4.png)
Offset
Offset is the distance between the core and first metal layer. In below picture, C is offset.
![offset-vlsi](https://ivlsi.com/wp-content/uploads/2020/10/route5.png)
How to calculate these pitch, offset values in real time project