If I copy and paset a footprint I cannot connect it to the existing ones. I must save and reopen the PCB file in order to make the copied footprint equal with the older ones.
What to do to avoit this?
I donât understand exactly what you canât do and can do after reopening.
But copying footprints is not a good idea as that way you got at PCB something that does not match the schematic.
OK, I didnât mentioned that I donât use the schematic, I create PCBs directly.
After paste I try to draw a trace from the copied one to an existing (older) footprint. But this is prohibited.
After save, close and open the PCB, I can do anything.
That does not work well in KiCad. Without the schematic, there is no netlist, and KiCad does not know which things to connect and from which to keep clearances.
I see. It means that I must live with this phenomenon.
Thank you very much.
There are some tools that can help with drawing a PCB without a schematic (Allowing DRC violations in the Interactive Router, manually adding netlist connections and the Wire It plugin, just to name a few).
It takes some effort to learn to draw a schematic and the things around it (library management, footprint assignment) but after the learning curve, drawing a simple schematic takes maybe 15 minutes, while helping a lot during PCB design, because of all the extraâs that come with a schematic.
Do you have some kind of screenshot or graphical overview of the thing you are trying to create? That can help us to give you some better advise.
I am grateful for your fast help and the willing to develop me.
This is the current schematic (a PSU from Multisim) I deal with.
1N914 is an arbitrary signal diode.
The first problem immediately is that there is no symbol for the BCM856 dual transistor (with SOT457 footprint). Now do I have to start to make a symbol? There will be other components which are not in the symbol database though the footprint for them is in the footprint database.
This is why I omit the schematic editor.
If you have a schematic like that, you should surely not attempt to make the PCB without entering the schematic into KiCad first. If you have the schematic, then KiCad will help you remember which connections need to be made, and also prevent you from making faulty connections (which is a part you already discovered).
A bit of double vision I just imported your drawing into a new KiCad project and put about 15 minutes into it. Result looks like:
Or, with the old drawing removed:
The zipped up project:
2024-05-17_asdf_cannot_connect_footprints.zip (49.8 KB)
The schematic is not finished. I did not look too closely at the values of the symbols, and I have not drawn the power section completely. I also have not done footprint assignment. Itâs up to you which size footprints to assign. For the transistors, I also used generic symbols without checking the pin order. (Same for the Opamp and other ICâs).I guess that if youâre halfway through creating the PCB, you already have an Idea of which footprints you want to use.
Footprints are normally assigned in the schematic, and then the whole thing (Footprints and netlist) is put on the PCB with PCB Editor / Tools / Update PCB from Schematic [F8].
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Itâs NOT true that you need a Schematic!
You can create NetClassâs and assign Nets in the PCB-Editor.
Use the Tools>Inspect>Net_Inspector to Create the Netâs.
Then, assign items (Tracks, PadsâŠetc) the usual way in PCB (as if the Netâs were created in a Schematic)âŠ
And, if desired, you can use âNetclass Widthsâ by the CheckBox in the trackâs Edit Panel. The Net field has pull-down with the Net selections after creating the Nets.
Click the Properties Panel in PCB on left-sideâŠ
True, but I never suggested it was the only way.
Yes, that is what I meant with âmanual entryâ.
But in practice, especially for a regular schematic like this, drawing the schematic is much easier then entering lists of texts. A schematic also makes it easy to verify and modify.
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You posted thatâŠ
I do agree that a Schematic is a good thing to have but, I would not say/agree â⊠does not work well in Kicadâ And, there is a Netlist if created in the PCB.
Manual creation of netlist entries is my definition of âdoes not work wellâ. Your definition apparently differs.
I also mentioned the Wire-it plugin. That may work in some cases, but verification is also a nuisance. I also have not checked whether it still works for KiCad V8.
Entering the schematic took me between 10 and 15 minutes, and itâs easy to verify or modify. I donât know how you could improve on that with another entry method.
Before trying to design my first KiCad PCB I have designed my symbol and footprint libraries. First was my strategy of library naming and I have made all libraries having at least one symbol (sometimes even not my true symbol but just to not have empty library). The same I have done with footprint libraries. Each my symbol has footprint associated with it so I have never even seen how footprint association process looks in KiCad V4âŠV7. When I have schematic I can directly go to PCB design.
In my opinion designing PCB without schematic you use only 5âŠ10% of KiCad offered power.
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@BlackCoffee and @paulvdh
There is no point in having stupid arguments in the thread. How about the Message System and keep things private???
The OP has found and copied part of a power supply from another CAD.
He wants a âquick fixâ to create a PCB.
Unfortunately for him, there are no quick fixes. Yes, you can create a PCB without a Schematic, but you really need to learn the Schematic system first to understand how to create a PCB without a Schematic.
eg. You two are discussing Netlists: I doubt the OP understands the term because he doesnât want to learn or be be involved with the schematic.
It is probably best to leave the OP to sort themselves out. 
-
I did not think that my original question started an avalanche of sectarian disputeâŠ
Nevertheless I would have been happy if you could discover why there is that phenomenon with the connection problem after a copy-paste. -
What is that âOPâ?
-
@paulvdh:
Thank you for the work, It is a time for me to try the start the design from a schematic.
Now I see that there is a lot of dual transistor type having symbol and I see how to place it (first click gives the first one, the second gives the second one), so with some cleverness I can get over the missing symbol problem.
Thanks to everybody for the reactions.
Gabor
Original Poster (or something like this).
Now this is curious:
In the screenshot below, I:
- Took a footprint from some library and placed it in the center.
- Used [Ctrl + D] to duplicate it and put it on the right side.
- Drew the two tracks. Both have the
<no net>net name, and track with is (presumedly) from the default netclass settings. - Use [Ctrl + C] and [Ctrl + V] to copy and paste, put the footprint on the left.
- When starting a track from this last footprint, tracks still get the
<no net>net name, but they are very thin (Width is zero), and donât connect to the other two resistors.
I can connect the very thin track from pad 1 to pad 2 of the left most resistor, and after that, the next track I start from the leftmost footprint does have a bigger width:
To me it looks there are some bugs in this area. But I do not work myself without a project or a netlist. There are just too many limitations when working this way. For example, KiCad can not distinguish between the two nets between the two left side resistors, and does not keep any clearance between them, and thus, it is very easy to create shorts, or too narrow clearance, which results in unreliable PCBâs. Without a project file, you canât even set up net classes, and the only âdefault netclassâ canât be edited. It just has 0.2mm wide tracks.
Because my own experience with working without a project (+ schematic + netlist) is very limited, I am not sure about this possible bug, and wonât make a bug report for this.
Why?
He found double transistors :
Because Iâm an idiot and didnât read his post properly. 
I deleted my post and Iâm out of this thread after too many wrong assumptions.
You need some restâŠ