open-source-silicon.dev

Hi,
I was wondering how I could change metal layers for PDNs (by default, vertical PDN is on metal layer 4 and horizontal is on metal layer 5).

```set ::env(FP_PDN_LOWER_LAYER) {met4}
set ::env(FP_PDN_RAILS_LAYER) {met1}
set ::env(FP_PDN_UPPER_LAYER) {met5}```
Add this in your `config.tcl` and update based on your need

Thank you, <@U0268926L04>. However, I wanted to decrease the number of layers to 3. I implemented these configurations:

`set ::env(GLB_RT_MAXLAYER) "3"`
`set ::env(GLB_RT_CLOCK_MAXLAYER) "3"`
`set ::env(FP_IO_HMETAL) "2"`
`set ::env(FP_IO_VMETAL) "1"`

(I used numbers because if I use met1, or met2,... it gives me an error.)

But still, I can not change the FDN layers with your configuration setups.

explore `runs/&lt;name&gt;/config.tcl` for more such default configuration

<@U03HDTXHFF1>
<https://github.com/The-OpenROAD-Project/OpenLane/blob/master/scripts/openroad/pdn_cfg.tcl> customize this file and point to `set ::env(PDN_CFG) $(DESIGN_DIR)/pdn_cfg.tcl` to use effective way