I suggest that a section of the User Defined Layer range (100-255) be made
unavailable in the library editors.
This would make the creation and use of these layers exclusive to the
Schematic and Board
editors.
Many ULPs nominate a specific layer to use to enable their functionality.
They depend on being in control of that layer.
The user or institution needs to manage these ULPs and layer usage so there
is no contention.
Another ULP approach automatically determines and uses the first unused
layer above 100. This is great for instances where the layer use is very
short lived with the layer being used akin to a scratch pad.
In theory, this technique should permit a ULP to be used in everyone's
environment for more but not if a library part could later add objects to
that layer. The functionality of the ULP is then compromised.
When the library part is ADDed
1) The library part that uses a layer defined on the board will acquire the
colors and layer name of that layer
2) The layer will get turned on when you may wish the user never sees it,
accidentally. The visibility of ULP objects confuses the user.
3) Unexpected library objects may cause the ULP to malfunction.
How many layers? I imagine deciding this could cause a lot of discussion
based on personal current usage of the layers.
Making it user configurable would solve that debate. Personally, right now,
the top 10 (246-255) would suffice.
Regards
Warren
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