What API should I learn?

[irneb]

Assuming the circuit builder.xls is where the programming works, this means it's a VBA thing inside Excel, which links to AutoCAD through ActiveX. Therefore you'd need to edit it using Excel's macros (VBA) and use the additional AutoCAD Developer's Help to see the VBA/ActiveX objects. Just take note that this VBA stuff will most probably stop working in the future ... it's already difficult getting it to work in MSO 2007 as well as with ACad 2009+.

If the xls is simply the data from which AutoCAD draws, then this could be any of all the previously mentioned methods (VBA, Lisp, .Net, ARX).

To answer your question about which Programming language to learn from for a newbie: The easiest to learn would be VBA, then AutoLisp / DotNet is a toss-up as to ease of use. The reason I say this is it's usually a lot simpler to start something which works in VBA, it's only when you come to advanced stuff that VBA would become a bit immature - then DotNet would be needed. Lisp is a bit of a difficult language to get to grips with at the start, seeing as it uses prefix notation instead of infix like VB/C/Delphi (infix would be ((1 + 1) * 4) = 8, while prefix would be (* (+ 1 1) 4) = 8 ) ... but once you get the hang of that it's just as easy (if not more so) than VBA to start something which actually works.

All that said, there's 2 things you have to ask: (1) "Do I want to continue programming in the future and maybe do some 'heavy' stuff?" (2) "Is there a lot of samples available so I don't have to re-invent the wheel?"

Depending on which of these is more important to you, I'd say:

1. Then go with VB.Net, you can get the VBExpress for free from Microsoft ... no need to buy an expensive Enterprise version. This doesn't mean lisp won't help in the future, but .Net is a "newer" "language" (not really a language, but a library). The VB, because it's easier to understand than the C# - which is a bit cryptic for a newbie (even for some experienced programmers). BTW, someone with VBA should do reasonably well with VB.Net.
2. Go with lisp as there's 20years+ worth of samples all over the show, and more often than not you'll find someone's already done what you're trying to do. There are some .Net stuff already, but as yet not as much as with lisp (by far).

So take your pick: AutoLisp or VB.Net ... I wouldn't advise anything else for the newbie.

[squatman]

Hi there,

I'm still trying to decide the pros/cons of each and even the possibilities of each, and also to understand how each can be implemented.

Can any of the method be used without a full version of AutoCAD being installed? E.g. you are running a VBA macro from Excel to populate a .dwg with border information based on data in cells.

Thank you.

[Ed Jobe]

No, COM/VBA requires the host application to be installed. The only way to use an exe without AutoCAD being installed is to license RealDwg.