[jmwilson]

It's a shame that circuit simulators, especially those derived from SPICE, have tended toward closed-source. It's nice that there are several free-as-in-beer options available, but a good lesson in the consequences of permissive open-source licenses. SPICE predates copyleft licensing, so software that was once open has disappeared into proprietary versions.

LTspice (sponsored by Analog Devices) is closed-source. The recently-released QSpice (sponsored by Qorvo) also closed-source. QucsStudio was taken closed-source by Qucs' original author, and he's not commented on his intentions in this decision.

Big companies typically open-source software when it's not part of their strategic business value, and offers community engagement benefits and good press. LTspice is kind of an advertisement for AD's chips. AD and Qorvo aren't remotely in the software and EDA business, so their decision to keep them closed is even more puzzling, but I guess the instinct of hardware companies is guard everything.

[baz00]

I think the thing is that no one in the industry gives much of a crap if it's open source or not. Most of the EDA users out there are on Windows so there is no reason to ship source for that platform either. The end users only care about the price which is why LTspice is popular.

Also worth noting that the SPICE engines have been modified heavily over the years in the open source side of things. Inside they look nothing like the original open source SPICE distributions.

When I'm, rarely, doing EDA work it's LTspice for simulation, KiCad for capture+PCBs and Excel for any calculation glue. All are chosen for price/performance rather than open idealism. One just happens to be open source.

[naikrovek]

there is little to no incentive for these companies to simply open source these applications. customers don’t care if the tool is open source or not, they just want a good simulation.

there is strong disincentive to open source these, because any competitive advantage your tool has with simulation is no longer a competitive advantage.

[jmwilson]

Last statement makes no sense since AD and Qorvo are in the business of selling silicon. These tools are marketing for their product lines.

It's like saying Google and Facebook are at a business (dis)advantage over the merits of Tensorflow and PyTorch, when their actual business is something completely different.

[Archit3ch]

At least the author of QSpice has committed to release the source of all models (including his tweaks for convergence). So you can take the transistors to a different SPICE engine with a simple netlist import.

[jmwilson]

The touted benefits of QSpsice include better numerical fundamentals, so who knows what happens when you take a tuned model and plug it into a different engine? The way it is described, the improvements to the SPICE engine could be valuable to anyone interested in numerical code and scientific computing, all the more reason why keeping it closed is a shame.