How do those pro motherboard designers, etc. decide how to lay out stitching vias? I've been having a bit of trouble finding a good reference.
Some of it seems a bit like "cargo cult" PCB layout...
Do you mean plane-plane vias? Electrical and thermal?
I don't really see it on motherboards. Too many layers to bother with, that are already good enough. only where pours/traces have to transition, in which case it's usually just an array of "enough".
Much more common in RF, where you have the ground boundary of a two layer board stitched around the signal paths.
I don't think I've seen many 2-layer (general purpose, digital or analog) boards with stitching, but I've made many myself. Just follow the negative space around traces, and stitch it anywhere you see a peninsula or overlapping or isolated region.
Tim
I'll try to post an example pic when I get a moment...
The RF microwave community has reasonable answers for that. Maximum spacing is determined by the shortest wavelength, and too much regularity can lead to resonances.
Even with extensive use of EM field solvers, it is still necessary to suck it and see, and then tweak.
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