Welcome to the CADSTARguys Blog - Information, hints, tips and my waffle on the CADSTAR Printed Circuit Board design suite.

Please note that all names used are completely fictitious and any thing written is my own personal opinion or knowledge and not related in any way to either my employers or their customers (or Zuken).
Also this is not a replacement for proper Maintenence/support and you should read the help files before asking anything techy:).

Wednesday, 9 February 2011

How High?

Depending upon what external applications you use with CADSTAR, your heights
may end up being all setup wrongly.

Historically CADSTAR has a height set on individual component footprints, used by both CADSTAR and the routers for height checking against areas etc. All was well many years ago when there was no other output options for your PCB, however along came the IDF translators to enable you to link to Inventor etc.

These need an attribute to identify the height, which is easily done by adding it to the part information. This could then be output and used allowing several parts of differing height's to use the same footprint with just the attribute value being different.

However, there are drawbacks to that method, that is that if you have several parts using the same footprint then CADSTAR cannot accurately do any internal height checking.

Along came CADSTAR3D and now BoardModeler Light (BML),  where BML can use either height however if you specify the attribute it will overrule the component height.

No problem - just specify the height in the part.
That seems to work well but what about any checking in CADSTAR? Although a design may be sent out to be checked for fitting in enclosures and clash detection etc done the PCB designer still likes to ensure it checks out well within CADSTAR before going into another application.

So how do we do it?

The solution is to make each part with its own component (no sharing) even if that means making several components where the only difference is the height.
I.E. "SO8 1.5mm", "SO8 2.1mm" and so on, the only difference is the name and the component height.

This way checking in CADSTAR can be done correctly while also enabling
external applications to also have the correct height.

Of course this means more work initially in setting up your library to work correctly, and possibly older designs as and when you need to however if you are investing the funds in BML then you also need to factor in the time required to setup your library and the 3D library accurately.


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