Update pcb from schematic or switch to pcb editor

Hi, In my schematic I have no lines crossing anywhere after I have done all my connections on the schematic. But when in tools I click update pcb from schematic all of the components are all over the place with those connecting lines crossing everywhere. It is an almost impossible task to move the components around in the pcb editor to not get any crossover tracks.
How can I get the ‘update pcb from schematic’ to actually follow my schematic? The wording ‘update pcb from schematic’ suggests that the pcb should be following the schematic. For instance in the pcb editor all of the resistors are lumped together.
This wasn’t much of a problem when I had a simple battery, resistor and led circuit. But now I have a much more complicated circuit.
Can anybody suggest how I can make this a simpler project because it looks just about impossible now?
Do you think in tools it may be better to select ‘switch to pcb editor’?

This is better than it used to be. :slightly_smiling_face:
In the bad old days, all the footprints were piled one on top of each other.
There are improvements on the way if my memory still works.

The connecting lines are called “ratlines”.
Also, to avoid confusion on this site: on a PCB there are footprints and tracks. On a Schematic there are symbols and wires.

The “R” for rotate is very useful for positioning on the PCB… make friends with this feature. :smiley:

I doubt it. Good placement of footprints is the greatest challenge.

No, because later, in your PCB layout, if you wish to change, rotate, alter anything on either the Schematic or PCB, updating will do just that, update the other drawing without moving symbols and footprints around your sheets.

The ratlines are all over the place and crossing in many places. If the pcb editor had placed everything as in my schematic there would be no problem.
Am I allowed to post the ratlines on this forum for anybody who may be able to move the components so that there is no crossover of tracks?
I can’t see a solution.

Once you get over the initial shock, start by moving things apart. Prioritize placement…
anything needing heatsinks move to the edge. move microprocessors out of the mess with their bypass capacitors. Place connectors and pots and LEDs where needed.

You’ll find when you have started to group items, everything looks much easier to place.

May be it is how you read it, but it means to:

  • delete from PCB all footprints connected with symbols you just deleted from schematic,
  • add right footprints for symbols that you have just added to schematic,
  • update all connections to be in accoredance with current state of schematic,
  • may be some other actions I just do not reckon.

Right positioning footprints at PCB is 90% of work when you design PCB.
You need not to not get any crossover tracks. At typical PCB you have at least 2 layers so you can cross tracks jumping with one on the second layer. If PCB is more complicated you can get 4 (6,8,…) layers PCB.
Some time ago I have described my strategy when designing 2 layer PCB and shown how PCB designed with this strategy can look like:

Now in V7 using my strategy you can hide GND net when positioning footprints as you have GND everywhere. That makes a connection lines mess simpler.

In V7 you can select a part of schematic and then move at PCB all elements from selection. That helps to make first order at PCB groping elements that are grouped at schematic. I can’t tell exactly how you do it as I didn’t used it yet and I am now at PC with V5 installed so I can’t check it.

(I’m finishing this post while others have already responded, so there might be overlap.)

You are clearly a novice, so it’s good to understand some basics of electronics design first.

The schematic is a symbolic representation of a circuit. It’s meant to be abstract, showing necessary things to understand how the circuit works. It doesn’t have to have anything to do with how the circuit is implemented in a PCB, other than that there must be corresponding components in both – well, at least mostly. There seems to exist schools of thought about how close a schematic should be to the physical design. Some think it must be purely symbolic, others think it’s good to go close to the actual implementation. In reality all schematics are somewhere between.

I’s completely legitimate to think about the implementation when designing a schematic if you feel that way. However, in most cases you shouldn’t decide the layout when doing it, and it’s not possible to lay out all symbols as they would be in the PCB. Usually it’s better to make it easier to read standalone, according to the functionality and not the physical implementation. It’s one of the most basic tasks of PCB design to move the footprints when you start a layout. It requires some practice but is far from impossible.

EDA programs don’t encourage planning the layout in the schematic, and KiCad doesn’t support it directly. There exists a PCB Editor plugin do position the footprints according to the schematic: GitHub - ian-ross/kicad-plugins: Miscellaneous plugins for KiCad.

When the design is large, the most important decision is to split it to several subsheets according to functionality. One sheet represents one functional part, often one central symbol and surrounding symbols. That division is represented in the PCB Editor, too, and there are several ways to select all footprints in a hierarchical sheet. You can also just select some symbols in the schematic and the selection is cross-probed to the PCB. By grouping the footprints you can design the placements of different functional parts of the PCB. Then you can start rotating the footprints and finding a good location for each of them relative to their functional section.


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