Electronic – Extract part of a PCB to make a new footprint in KiCad

In CvPcb there is the "View selected footprint" in the top toolbar.

Once you press that button, a new window pops-up where you can see your footprint.

This new window allows you see the component and has a grid from which you can find out the size of your component. This grid is also selectable by right-clicking the grid and choosing whatever grid you want from "Grid Select" option.

If you mouse-hover on one pin, on the bottom of the window there are X-Y coordinates from which you can tell the distance between the pins. This one, from the example, has 5.08mm * 2 = 10.16mm = 0.4inches distance between the pins.

The workflow in Altium which I got used to for 2 years was that when you make a custom component, you make all the stuff at once - the schematic symbol, then a footprint, and assign pins etc. which makes sense to me.

The workflow in KiCAD which I've been using now for about 1-2 weeks is totally different. You do the schematic, and have schematic libraries, and then you make a net list and assign footprints. The footprints may not exist yet, so you can make them at this point if you have not already made them. You can do altium-like workflow if you try really hard, but KiCAD does not make it easy, and documentation/YouTube videos are all using old versions so you can never really get a good concrete way of doing things. That is the glory of an ever-changing open source project.

There is a magical footprint wizard which has an icon up the top in the footprint editing program in KiCAD. The footprint wizard was useful to me to make SIP pin headers quickly. There IS a QFN footprint maker in the wizard, but maybe not a QFP - have a look.

Otherwise I suggest you learn how to make a footprint pad-by-pad, and using the datasheet by the manufacturer and their "suggested pay layout" which is almost guaranteed to be there, or it's a standard footprint diagram you can get from elsewhere.

The easiest way to do it in KiCAD is to set the "user grid" to the correct X and Y pitch so that you can just plop down the first set of pins, and then change the grid again to get you to the side set of pins, and then top, and then the remaining side. The problem with KiCAD is it's hard to measure stuff, and the grid settings are so awkward to get to, but you always have to use them - there may be hotkeys you can bind.