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Hey folks, I think we need to figure out a comprehensive LDraw object model. Something that can be presented simply, and easily ported to various modern programming languages. A comprehensive class diagram would be a great start, and some code to (...) (23 years ago, 9-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Here's my first contribution, a rough outline of a class structure. *** LDRAW LINE TYPE CLASSES *** abstract class LineType - ancestor class for all line-type objects + class LineType0 - comment line-type + class LineTypeCommand - command (...) (23 years ago, 9-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) > (Maybe not too much, let's keep it lean and mean.) At the least, I > think we should make the object model workable in C++, Java, Perl and > Python. (...) This is interesting. I wonder what we can do as far as making it both comprehensive (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Aren't all of these classes Abstract? I mean this is only a template for implementing a Class Library right? Are you planning on actually filling in the code also? or just defining the interfaces? (...) So far you've got a few more levels in (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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How about an LDraw DAT model reducer - something that hacks out the insides and leaves nothing but a hollow shell? This way you could port it to platforms that can't handle so many polygons, and also render in realtime. It would kind of be like (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Actually this brings up a different issue. I haven't put alot of thought into it yet, but I think it would be useful to add information in the part files that would allow a program to differentiate between geometry that represents 'outside' (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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I like this. I don't think I can contribute that much. I would like to though. I have been working in Java with my animation program ((URL) and I can contribute a class for LineType1. Most useful is a rotation function that I would like to think is (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) The base class is abstract, the ones not marked "abstract" aren't. This class hierarchy is actually the class library I whipped up over the past week. About 95% of what I posted here has working code, but I didn't want to push any of that if (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) I'll have a better answer for this when I port my Java implementation to Perl. But yah, I guess "comprehensive" and "generic" don't quite mix well. I want comprehensive, in that this library could be used for many different methods of (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) IIRC (and I wish I could find the reference) the LDraw spec does support this. It depends on the order of the points in the polygon; e.g. clockwise points out, counterclockwise points in. Or something like that. But last I heard of this, there (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) <snip> First, this is a nifty idea. Objectifying this is long overdue. But I was struck wondering, is this trying to objectify the current dat format as it is, or an ideal one as we would like to see it be... Also, are you a fan of the MVC (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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"Sproaticus" <jsproat@io.com> schrieb im Newsbeitrag news:GrA7CA.24y@lugnet.com... (...) Shall this lines be only container classes or shall they have the working code? If they have working code, they are heavily depending on the target system (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Standard libraries/classes for reading, writing and processing LDraw and MPD files is certainly a good idea, but I am not certain rendering functions should be a part of such a library although it is an obvious extension. Jacob (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Well, this raises the point: what ideal is the LDraw format aiming for? I don't think it's really going anywhere; any real change to the format would break compatability with the legacy LDRAW.EXE. I'm proposing a class library for the existing (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) The way I designed my stuff is that the code in the linetype classes manage the objects they contain -- mostly just allocation, serialization and stringification of a matrix or a list of vectors. However, any rendering or parsing behavior is (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Well, while I haven't tried it, I'm fairly sure that my implementation of MPD-handling in LDView would happily load an MPD file as a subfile of another MPD file or a dat file. :-) --Travis Cobbs (tcobbs@REMOVE.halibut.com) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Backface culling (BFC) is what you are describing, but it isn't what Kyle was asking for :-). In traditional realtime 3D rendering, polygons only have one side. The back side is literally non-existent. It doesn't get drawn at all. This is (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) I can definately see the benefits of a standard library interface. Even an implementation might have a lot of uses. I just think that you will get the best design for the interface, if you forget about how you or anyone implemented it in the (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Ok. Up until now I've been under the impression we were trying to come up with a pure interface definition, independent of any particular language, platform, or implementation. When I asked if they weren't all abstract, I was envisioning (...) (23 years ago, 10-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Yes, What you're describing does sound like BFC to me. As someone else (travis I think?) said, BFC is a useful optimiziation for reducing the number of surfaces that need to be drawn. But it's not the same thing I was talking about. BFC (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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"Sproaticus" <jsproat@io.com> schrieb im Newsbeitrag news:GrBy72.EJI@lugnet.com... (...) Conclusion: The LineType-classes are wrapper classes for the lines in the dat files. Simple in- and output methods are included, also simple transforming (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) A couple of different approaches to this have been discussed before. I think the most generic solution was to implement a 0 DETAIL <level> meta-command, that would identify the detail-level of the following lines. A 0 detail level indicates (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Could you give us an example? By looking at what you've written, I don't understand if one needs an ending tag, or not, to complete the '0 DETAIL' command. Where in the text of the file would this go? How would it look? Thanks a lot. Much (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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"Kyle McDonald" <kmcdonald@bigfoot.com> skrev i meddelandet news:3C671582.801040...oot.com... (...) If the parts are BFC compliant, there's no need to tag for 'top', 'left' etc. as this information is already there in the surface normal (with much (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Well again BFC is only useful for culling surfaces that face away from you. It doesn't really do anything for faces that face you but are blocked by other faces. When I talked about top, left, right, etc, I was envisioning some system by which (...) (23 years ago, 11-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) OK. This is sounding very yummy. When can we start using the frameworks. (...) Nonsense. I got to work and home just fine today, and I even found parking right across from where they had the opening ceremonies. :-) James (23 years ago, 12-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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"Kyle McDonald" <kmcdonald@bigfoot.com> schrieb im Newsbeitrag news:3C66F9C8.207030...oot.com... (...) I have made two charts, one for file loading and one for file structure (URL) this location I can place futhermore our conclusions, when we get (...) (23 years ago, 12-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) I'm hoping within a couple of month or so (beta with a month or so), but it really depends on how this project goes, and the schedules of anyone who wants to contribute. (...) That shattering sound you just heard was my jaw hitting the floor. (...) (23 years ago, 12-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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"Bernd Broich" <bernd.broich@online.de> schrieb im Newsbeitrag news:GrF5JD.5zI@lugnet.com... (...) I found a free UML tool that works and made a class graph showing the classes, we talked about. The tool, Poseidon for UML, is java-based and (as (...) (23 years ago, 16-Feb-02, to lugnet.cad.dev)
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| | Re: A comprehensive LDraw object model
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(...) Okay, this thread is way too old and I feel that I owe an explanation for my tardiness. I apologize to everyone who was looking forward to a usable prototype; I hope I didn't set expectations too high. Lately, I've been heavily involved in (...) (23 years ago, 7-May-02, to lugnet.cad.dev)
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