Apologies for the messy image, but I’m only allowed one attachment on the post as a new user.
TL;DR - I’m supposed to have islands on this board - they’re there, but in the bottom copper layer along with the ACTUAL bottom copper, so (pretty much) everything on the back is connected. How do I use the existing shapes to cut out breaks in the solid copper back?
In depth:
At some point, a revision was made to this board, with someone taking the separate drill, silkscreen, front copper, and back copper done as autocad files and converting it somehow to .grb files - apparently a straight up import, because there are dimensions and other text/marks on the copper layers. This existing, messy as hell file did line up with the physical boards (bottom picture on the attached image), but a new manufacturer couldn’t make any sense of the… let’s call them misdefined layers.
I was able to use the gerber viewer in KiCad to convert the existing gerber (picture 3 in the attached image) to a KiCad board file (picture 2).
Unfortunately , the gaps in the pour were apparently MOSTLY done as keepout layers, which WERE imported - but as Bottom Copper , just like the rest of the bottom layer - so the functionality of the board is gone. How can I use the existing shapes to break the copper pour as intended?
EDIT:
Forgot to mention - trying to change those Keepout shapes from Bottom Copper to Bottom Courtyard did not prevent the complete fill on the board
I’m guessing that the missing bits were hacked into the gerber files in some “marginally compatible” way.
How is the small “T” shaped things imported? Is it a copper zone or a graphic object on a copper layer (Same for the big zone).
They shold both be copper zones, and connected to different nets. When they are connected to the same net, then KiCad merges them together. Usually there is no netlist info in Gerber files, so KiCad does not know what the zones are connected to.
I’d say that KiCad already did a great job. There are no zones, pads or footprints in gerber files, It’s all just copper features and “flash codes”.
Have you seen my (3 year) old tutorial:
It’s got a section of replacing imported copper features with real footprints.
If it (the outer shape) is already a zone, just assign a different nets and it should work. You only need to manually subtract polygons if the outer area is also a polygon.
Zones and polygons are different things (top and bottom respoectively):
E.g. here is a polygon inside a zone with net GND - the zone automatically provides clearance to objects with different nets (or no net), but polygons are always the exact shape as drawn.
Unfortunately, just sketched one of each to check, and I was using the wrong terminology - they are polygons, not zones - even the big one, @paulvdh
But I did find a better way to illustrate my question - if I go into View → Drawing Mode → Sketch Graphic Items, all the outlines I need are there
How do I bring that across to the final board? Is there a better way than using that Sketch Graphic Items view to trace all the polygons with actual zones (and double clicking the vias in said zones to manually define the nets)?
I did grab the test build, but I’m not seeing any way to cut polygons
Still limited to one image per post, unfortunately.
Top one is sketch graphic items view
The shapes already have those outlines, sketch view is just a way to see it without the fills (there’s also an opacity control in the right hand panel, under the “Objects” tab)
I suggest to delete the “main” polygon and replace with a big fill zone the same size as the board that you assign a new net called GND. Then it will flood-fill the whole areas with copper, but maintain clearance to the other items:
Any pad you assign to the GND net will then connect automatically. This will cover nearly all your needs that you are currently using a polygon for, I think.
Boolean substration is in “Shape Modification” when you right click with a selection of 2 polygons.
You can’t post more images or attachements because you haven’t read 30 topics in 5 categories yet.
