a format for the STRUCTURE of (feature-based, parametric) CAD models. There are already too many formats for the 3D geometry itself, which may be referenced in the XML format if needed.
SVG is great for drawing (maybe even sketch..) GEOMETRY (See
formatting link
). But SVG does not say anything about the structure of the documents (which parts are referenced, view characteristics properties, tables etc.). I'll do a CadML of a SW drawing very soon as an example.
Right, but I make a distinction between the geometry description (sketches, features, dimensions) and the resulting 3D (B-REP) representation (edges, faces...) which takes a lot of space but can be rebuilt from the description. However, If you keep everything in a properietary file format, admin tools will be CAD-specific (they all are...) My idea with cadML is to export admin+geometry structure as XML, which can either be stored in a separate file or in the cad file in a zone that can be read by an external tool.
Yup. I'd like to be able, one day, to re-build a part completely from its cadML description, allowing backward compatibility and interoperability between CADs...
Well, if Philippe's CadML is the storage mechanism, revision control becomes easy. There are dozens of time-tested, powerful tools performing revision control for source code text files already. CVS for example. Imagine being able to create a new 'branch' in your model where you explore an alternate way of modeling a dozen features, and then being able to back out of all those changes, returing to the model you started with.
Is it using one file to store all modelling information (huge and slow file?) or one file for each rev.?
So...where's the free tool that works with SW then ;-)
I know that many users are already quite confused with configurations (maybe not here but generally) and if there is going to be something quite similar but for revisions is it all getting too complex for most of the people?
Well, for something like CVS, it is a single file. The CVS system injects text to mark what has been added/removed, etc, between changes. The end user never sees the injected text, as it is stripped out when the user 'check out' the file.
CVS overall, is one of the less intelligent systems. IBM has a current open source project called Stellation which has a finer grained aproach to source code storage, in which individual program elements (i.e. a function declaration) can be tracked. As a user, you can say, show me the function foo() as it was last Tuesday at 11:30 AM, and *poof*, it appears.
Once again, this is for source code, but my mind gets spinning when I think about the possibilities for other areas. A solid model, when expressed as text, isn't all that different from a computer program. Interdependencies between smaller elements are used to create larger elements and so on.
I suspect that configurations are overused. I avoid them for the most part because of the problems they cause when the time comes to make drawings and BOMs.
Revisions are another matter. There are two types of revisions: public and private. Public revisions are the ones that go through official channels to let mfg, sales, etc know that something changed. Private revisions occur when I think of an alternate way to do something and want to explore it. Currently, you can use configs for this, but it is cumbersome. You have to pay close attention to suppression state, and even closer attention to avoid changing dimensions globally that you only intended to change in the current configuration. The other option is to copy the file and then hack away on it, but then you may have issues if the 'hacked on' version turns out to be better. You have to track down the places the part may be used and so on.
I want the freedom to fiddle with things without having to worry about getting back to where I started. If a nice revision control system for public revisions can come from that as well, I'm all for it.
Little bit afraid to see a part that has let's say 10 configurations and each has several revisions and all that information is in one file..there should be a tool to strip off some revisions that you propably don't need anymore (but you never really know what you need and what you don't:-))
Only "problem" for me seems to be that you can't have the same file name for part and a drawing, but because..of course...I know that I'm using configurations it's not a problem at all. Custom Property softwares can handle configurations...and if they don't you should switch to one that can. Never had any other problems..
I agree. Maybe some day..it's good to have something to dream about :-)
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