# How to generate a SPEF (`write_spef`) including coordinate information?

Tool: Parasitics Extraction

Subcategory: SPEF format

## Conversation

### xlindo
As the default flow, there is no coordinate information in `*CONN` following each `PORT` in the generated `6_final.spef`, which is not in coincidence with a normal SPEF format.

E.g., no `*C` bolow,

![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/8579640/488691da-2217-4dae-980b-da833f9bbf79)

```
...

*CONN
*I *572:B I *D sky130_fd_sc_hd__nand2_1
*I *571:Y O *D sky130_fd_sc_hd__nand2_1

...
```

Compared with another example in a book,

```
*D_NET *5423 2.69358 

*CONN 
*I *14207:D I *C 21.7450 94.3150 
*I *14205:D I *C 21.7450 90.4900 
*I *14211:Q O *C 21.4900 83.8800 *D DFFQX1 

*CAP 
1 *5423:10107 *547:12722 0.202686 
2 *5423:10107 *5116:10594 0.104195

....
```


Any boss help me?

### maliberty
Coordinates are optional in spef so this is valid.  There is code to generate coordinates but we've never used it.  We could try enabling but I can't make any guarantees about what it will produce.  Do you have a use model for these or are you just comparing to what a book shows?

### maliberty
I've added a -coordinates option to write_spef in https://github.com/The-OpenROAD-Project/OpenROAD/pull/3434