X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com Message-ID: <53BDBC7A.5070709@sonic.net> Date: Wed, 09 Jul 2014 15:04:42 -0700 From: Dave Curtis User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121028 Thunderbird/16.0.2 MIME-Version: 1.0 To: geda-user AT delorie DOT com Subject: Re: [geda-user] pour clearing around pads References: <201407091750 DOT s69HofTL021912 AT envy DOT delorie DOT com> In-Reply-To: <201407091750.s69HofTL021912@envy.delorie.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Sonic-ID: C;zj9mB7UH5BGNW2uUdPQXfw== M;2vqAB7UH5BGNW2uUdPQXfw== X-Spam-Flag: No X-Sonic-Spam-Details: 0.0/5.0 by cerberusd Reply-To: geda-user AT delorie DOT com On 07/09/2014 10:50 AM, DJ Delorie wrote: >> I think any layer objects embeded in footprints (might as well include silk and copper in the same way going forward), ought to reference predefined symbolic layer name or ID. >> >> "TOP-SILK" "TOP-MASK" "TOP-COPPER" "INNER-COPPER" "INNER-ANTI-COPPER"* "BOTTOM-COPPER" etc... >> >> *(inner anticopper might need some thought, possibly not one for today!). > Yeah, IMHO symbolic layers is a must. > > I also think we need a way of "stacking" or "nesting" drawing layers > within a physical layer to do fill/cut/draw operations. For example: > > * "Fill" - positive, first rendered, used for power plane polygons > * "Cut" - used for keep-outs, and cutting planes into sub-planes with traces > * "Trace" - used to draw traces over polygons (clear polygons but ignore cuts) > > Each layer needs a positive/negative flag, so you could (for example) > draw negative text over a filled rectangle. > > But given that footprints might have their own fill/cut/trace layers, > which may be drawn on top of the board-layer cuts, we need to be > flexible in making these stacks... > > * board-level fill > * board-level cut > * footprint-level fill > * footprint-level cut > * traces I agree with all that. The need for a footprint-level version of the layers distinct from the lay-out level isn't extremely clear for me, but I assume that makes internal operations easier to sort out. > > but if you want to support "sub-layouts" it gets even more complex. > > Perhaps a heirarchical design? > > * board-level fill > * board-level cut > * sub-layouts and footprints -> > * . . . > * . . . > * . . . > * board-level traces > > And all that is just *per layer* And what are the chances of this happening in pcb? Is that a doable change? So here is another one. I saw my KiCad-using friend (at the "Wednesday Robot lunch" where we talk about robots and eat Thai food...) the topic of buried parts in multi-layer boards came up. So that got me thinking about how to represent voids. The void is a cut into the substrate of the lamination(s) above the component. It seems to me this is another footprint layer, with a Z-thickness, that causes voids in adjacent layers depending on the particular stacking order and layer thickness. I don't plan to build any of these any time soon... but it seems like the concept should be considered along with all the rest. >