@dc42
what sort of machines do your customers use - in other words, what is your special case?
This is a pick and place machine. All I care is to get from one point to another as fast as possible, but smoothly. The catch is (if it is a catch) that the machine sizes vary. For this discussion, the main point is the Y axis. The gantry travels on a moving bar, which can be different length. Also, some customers have done modifications to their machines, and some (not necessarily paying customers) use my software on other machines, not sold by us. I'd like to support them as well. (An anecdote: My best customer, by far, didn't pay for his machine. But he paid back by far more value by improving my open source design.) So, one fixed value determined by us is unlikely enough.
I am not aware of S-curve acceleration being important in any of these applications.
On the other hand, I am very confident that some acceleration management is necessary. It doesn't have to be s-curve, but a constant value is not sufficient. (FYI, this is where I gave up on Duet and decided to wait for 3.5: a thread )
RRF provides a custom input shaping mode...
And apparently, this is where I will look next. As said, I rather use something that doesn't need extra hardware and setup effort. However, I do know I need a better control board. The Duet3, with its software features and powerful drivers is way above anything suitable that I've come across - and the support given on this forum is superb. I'd love to use it.
I know s-curve works (for this application) and would be a simple, cheap and sufficient solution (for this application) . There were some hints that RRF might get it one of these days, perhaps on 3.5, so I asked. Nothing more in it, I'm not arguing it is a necessary function for RFF or better. I also accept (with no hard feelings) that it is not beneficial to your main customer base and you consider input shaping being superior. You can't please everyone, and if this time I "lose", so be it.