First, This was enough fun that I lost most of this evening…
Now that I’ve had a taste, I want more (of course) 
In transient response, I’d love to have more measuring tools similar to what is available on an oscilloscope. I circled the time value in “red” because I’d rather have frequency displayed here, like 6.58Hz. On a scope, I can build a small table of measurements for multiple displayed waveforms and library functions. I’d love to do this in KiCad’s simulator. The closest I could find is “Perform Fourier Analysis…”, which looks like the table came out of NGSPICE in the bottom window.
Really cool, but, just like a scope, and since NGSPICE is fast, I’ll tend to do lots of small runs looking at the “dashboard” I built for specific feedback on my circuit performance while I fiddle with my design. Good measuring tools help, during design, and after the fact on the bench.
I’ll probably want spectrum analysis type features in the frequency domain in AC Analysis.
And for S-Parameters, I’d like a Smith Chart in KiCad, among other things. I hardly know anything about S-Params, so this will be a learning experience, hopefully not too painful. I don’t think I could solve a Maxwell Equation anymore to save my own life unless I set aside a large block of time.
And on my current project, I’ll be looking into IBIS modeling to see if I can get any more insight before sending to FAB.
Thank you for these new tools! This was an exciting evening with KiCad v8 Release Build.
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BTW, I blew up v7 trying to see how far I could push things. Now NGSPICE won’t run in v7. I may have to reinstall. I don’t know how to provide any better feedback on what happened, other than immediately after pressing “Sim Command”, I get this dialog:
If I press “Ignore”, KiCad v7 locks up and I have to use Task Manager to kill the process. I’m still finishing a design in v7, so I’ll have to make sure I haven’t broken the installation.
Application: KiCad x64 on x64
Version: 7.0.11, release build
Libraries:
wxWidgets 3.2.4
FreeType 2.12.1
HarfBuzz 8.2.1
FontConfig 2.14.2
libcurl/8.4.0-DEV Schannel zlib/1.3
Platform: Windows 11 (build 22631), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
Date: Feb 21 2024 14:46:19
wxWidgets: 3.2.4 (wchar_t,wx containers)
Boost: 1.83.0
OCC: 7.7.1
Curl: 8.4.0-DEV
ngspice: 41
Compiler: Visual C++ 1936 without C++ ABI
Build settings:
KICAD_SPICE=ON