Hello @Tim Edwards, I wanted to make the parasitic extraction for my layout so I can make a post layout simulation, but there are some things I don't know how to do. The command lines I've entered are the ones below:

extract all
ext2sim labels on
ext2sim
extresist tolerance 10
extresist
ext2spice extresist on
ext2spice rthresh 1
ext2spice

My main problem is how to extract resistors from the layout to SPICE. I don't understand from the documentation how does the tolerance work. Also, when I do extresist I receive the message

"Bad Device Location at ... "

various times. With those lines, I don't get any resistance at the output SPICE file. If you need any of the files, let me know 😄.

Take a look at the script from user JC a couple of posts up. That script is what you want to use. You will get the "Bad Device" errors if you don't flatten the circuit. Also, you want to set option "cthresh" to zero (to capture all parasitic capacitances) but not "rthresh" (which is a mostly misunderstood option that doesn't extract resistances in any way meaningful to ngspice or any other SPICE simulator).

Thank you very much, it worked! If it doesn't extract anything meaningful for SPICE, what does

rthresh

do?