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step mapping best practices

drdanmc

I have some questions about best practices for step mapping.  In our symbol (footprint) library, some of them are very specific for a particular vendor component and so it is easy to just edit the .dra file to do the mapping.  But we have some others where one layout symbol is shared across multiple devices.  So far the only thing I've been able to do is to open the 3d mapper in the layout and under 3D mapper -> Device, set up the mapping.  But of course this is tied to a particular board design and so that work gets recreated every time a particular device is used.  Also I've noticed that sometimes some symbols and devices that are placed in the layout won't even show up in the list in the 3d mapper and I have no idea why.

So is there any "standard" way of specifying a device level mapping that will get used automatically?  Or do I need to maintain a large .map file with entries like:

  <MapItem device="device_name" package="symbol_name">

and then load this mapping file manually into the layout?  Would there be any simple way to automate this or is the process to manually first do place->update symbols to update the mapping in the .dra files and then in the 3d mapper import a map file for the device level mappings?

Also, any idea why some symbols and devices that are place in the layout don't show up in the 3d mapper window?

Thanks

-Dan

  • excellon1
    0

    Hi Dan,

    It would be better to add the STP file to your footprints in the Symbol editor when you create a new footprint or edit an existing one. This is because the the Step Packaging Editor creates an XML file of the mapping to the footprint. When you work this way and do a new design your 3d view will contain the stp model. If you have a legacy design that does not have a step model you could add one in within the PCB editor.

    A better way would be say your older design had an 0603 footprint that at the time the design was done you didn't have a stp model, but later on added the step model to your library. Assuming your footprint .dra name did not change, You could refresh your symbols to update the legacy design so the stp model would be available.

    Look under Place > "Update Symbols" to do this. 

    From the mapping perspective when you edit a symbol or create a new one & then add a STP File to the symbol, the Step Mapping Editor will create a folder with the mapping
    information in the form of a XML file under your footprint library. The folder is named "stepFacetFiles4Map" Within that folder you should see the xml files with the same name of the symbol you added a stp model to.

    By default when you create a PCB Footprint in the symbol editor, provided the symbol has a "Place Bound top" Shape & that shape has the height property added to it then in the 3d view you will see that. Usually this is not as pretty as having a stp model but it would represent your part. Originally the Place Bound class was used to create a 3d view
    of the footprint.

    If your symbols do not show a 3D view it could be because there is no place bound top shape in the symbol or there is no step file, or additionally the path to the stp file is incorrect. At a bare minimum when a symbol is created it is a good idea to have the place bound top shape with a height property added to the symbol.

    Best Regards.

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