Question on the Grid


#1

Just wondering if there is a good reason that the grid modifications in the Schematic are tucked into a drop down menu versus in the PCB layout is out on the fringe of the 3D screen?


#2

Makes sense to me since you probably never have to change the grid in the schematics but do it all the time in the layout. (I guess I could be proven wrong but that is my experience anyway)


#3

Welcome to yet another lovely KiCad quirk!

For the most part, there is little reason to change the grid setting once set to 50 mils.

The Eeschema menu item may state, “Grid: 50.00 mils”, but there are no actual size calculations done (this can be demonstrated by changing the sheet size).

If you use your own custom symbol libraries that have all pins on the 100 mill grid then that makes alignment half as critical when drawing out schematics.


#4

Okay, yeah I kinda figured that to be the case but I thought I’d put it out there just to see if anyone had some important idea as to why.

I like asking why…

Just ask my high school chemistry teacher…


#5

Well, a couple reasons.

  1. Schematics are simply logical representations of the function of the circuit. Size and scale aren’t really necessary.
  2. But, more importantly, in KiCad there is no object snap in EESchema (yet). So if your wires aren’t pretty much exactly on the pin ends there isn’t an electrical connection. Keeping to a grid where the pin ends are all on grid points is the only way to successfully create a schematic that you can pull a netlist from, and therefore build a board.

I’ve seen some teaser videos of coming attractions for features that are being worked on for v6 and higher. (No indication on if or when they will make the cut for a specific release.) One of the features was object snap (end points, mid points, etc.), but I don’t remember if it was PCBNew or EESchema that the object snap was being targeted towards. Hopefully both since the next big thing is GAL for EESchema, so the drawing API should hopefully be similar.