 | | Re: Comprehensive meta-command list
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Paul Gyugyi wrote in message <37F8CE0C.13D582C9@g...yi.com>... (...) Cool! This could be very handy. I'll add it to the DAT format page I'm writing. -Gary (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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Lars C. Hassing wrote in message <939050465.592693@ns.cci.dk>... (...) True. But when manually examining a file, if you come across a 0 INVERT you wouldn't know whether this was the beginning or the end of the inverted references, without a bit of (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex [DAT]
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It seems to me that there are two major "camps" in the CW/CCW debate. A. Face-by-Face Method This method suggests that CW-ness be ultimately evaluated on a face-by-face basis. Each quad in a primitive or part would hold a value of CW,CCW, or (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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(...) True. '0 INVERT END' may be allowed as a syntactic convenience to authors. Or 0 INVERT could be rewritten as 0 INVERT [ON|OFF|TOGGLE] where TOGGLE would be the default action. (...) [example snipped] 0 INVERT is different from 0 FACE [CW|CCW] (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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(...) Hooray! :) (...) Hooray! :) Steve (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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Jacob: (...) Steve: (...) Jacob: (...) It happens every once in awhile. Actually, which approach *would* be better? Examining the transformation matrix to determine the state of inversion, and adjusting the CW/CCW setting to correct for it, would (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Interpreting the proposed FACE meta-command
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(...) Recognizing multiple forms of the command shouldn't add much to rendering. Each file can be parsed once, and then the post-parsing results cached, for later re-reference. The FACE meta-command would be stored as an opcode and a single (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files [DAT]
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(...) Forgot the footnote: 1- There's an interesting distinction between 'valid' and 'well-formed' contructions. LDraw will allow line-breaks as whitespace in commands, so: 1 16 0 0 0 1 0 0 0 1 0 0 0 1 3001.dat is valid, but it's not well-formed. (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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Steve: (...) Yes. (...) Yes. Play well, Jacob ---...--- -- E-mail: sparre@cats.nbi.dk -- -- Web...: <URL:(URL) -- ---...--- (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Track names (was Re: To Tore Eriksson)
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(...) I'm curious Chris, in what sets was that the case ? And do these gray ones have those "negative" tapered ends, just like the old blue track had ? In lugnet.cad.dev, Larry Pieniazek writes: (...) Gimme a set number for "the wildwest miningish" (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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(...) Yes, they do. In the example above, the first meta-command, 0 TRANSLATE 20 0 0, would persist until the end of the file. (...) I think I know the answer to this question, but just to be sure: is the 0 INVERT meta-command transparent to (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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(...) I've been thinking the exact opposite -- mirroring should be a valid method for turning subfiles inside-out, and the software doesn't need to do anything special to deal with it (except to notice the inversion, and pass that info on to the (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Interpreting the proposed FACE meta-command
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(...) Why not recognize it all ways: 0 FACE ACW 0 FACE ANTICLOCKWISE 0 FACE CCW 0 FACE CLOCKWISE 0 FACE COUNTERCLOCKWISE 0 FACE CW 0 FACE DOUBLESIDED 0 FACE DS 0 FACE UNKNOWN This adds a bit to the parser, but not so much. The recommended standard (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) No (like Gary said). Two reasons: 1. The 0 FACE directive would be an operative switch, not a global setting. This is convenient, but it is also necessary in some cases. Most importantly, it would allow the 0 FACE meta-statement to appear (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) That's what we're doing now--figuring out what the standard should be. Both the function and the syntax. But "standard" is an odd term in this case. In my mind the LDraw standard is defined as "code which is recognized and interpreted by (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) Neither do I, but I also know how hard it is to visually check a part for errors. (...) How does that work? Is it based on what the majority of the rays deterimine? I probably need to re-read some of the messages in this thread, to get a (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: New Group Idea
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OK, so my minifig-scale models of Barbie and Tux the Penguin have nowhere to go? -gyug (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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There will be support added for "0 INCLUDE filename.dat" in the next release, which will insert the text from filename.dat into the current file. This differs from a type 1 line, since the scope stack is not pushed and popped. For example, "0 COLOUR (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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Gary Williams wrote in message ... (...) No, never needed, since "0 INVERT" is a toggle! (...) Since INVERT is directly related to the CW and CCW parameters of the FACE meta-command, why not let it be yet another parameter to FACE ? I think the (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) You need to have someone to check the parts, take a look at the picture at (URL) (from 105.DAT), there's a missing face and the program won't be able to handle that. There are other parts like that, just start checking and you'll see. Leonardo (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Interpreting the proposed FACE meta-command
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Jacob Sparre Andersen wrote in message ... (...) I was just trying to be consistent...:) I'd be just as happy if they were all spelled-out. But I'd like to avoid supporting both abbreviations and the complete spelling. Every additional test that (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Interpreting the proposed FACE meta-command
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Gary Williams: (...) Very sensible (now that Steve has convinced me). (...) Hmm. I don't like it, but we have already abbreviated (counter)clockwise, so it does make sense to abbreviate double-sided too. :-( Play well, Jacob ---...--- -- E-mail: (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Interpreting the proposed FACE meta-command
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Michael Lachmann wrote in message ... (...) Here's my take on the matter. The meta-command: 0 FACE <CW|CCW|DS|UNKNOWN> ...should only be used to indicate the order of the vertices of the polygons _in the file that contains it_. If A.dat has a '0 (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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Jacob Sparre Andersen wrote in message ... (...) also (...) but (...) the (...) an (...) Is this the standard now, or at least could we make it the standard ???? Mike (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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Steve Bliss wrote in message <37f6c258.270062819@...et.com>... (...) 30 (...) Does that mean if a program would find the CW directive it can assume that every-thing in this file is compliant? E.g. the program would not have to test if possible (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
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| | Re: New Group Idea
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(...) I think Tore was only joking. (Note that he followed his comment with a B-) smiley...) --Todd (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) I really don't like programs that need user interactions for such job! Thus I tried to cast enough rays so that all the faces are being oriented correctly. Now all the std bricks are OK, without any assumption about the fact that they are (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) you should consider that there are a lot of such groups of sides in one brick! Thus, the approach described by Leonardo is better: (...) Now, my main problem is: how can I find enough time to translate and check all the bricks! I guess my (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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Jacob Sparre Andersen wrote in message ... (...) These operations nest, rather than override, if I read (URL) correctly. (...) I think that would be best. -Gary (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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Bram Lambrecht wrote in message <19991003.083644.509...no.com>... (...) No. Our software will detect mirror operations and correct for them. -Gary (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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(...) I mirror sub-parts often in my models (for hoses, wings, etc.). Would this require an INVERT? --Bram Bram Lambrecht / o o \ BramL@juno.com ---...---oooo-----(_...o---...--- WWW: (URL) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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Steve: (...) Hmm??? Yes you're right (again :-). Play well, Jacob ---...--- -- E-mail: sparre@cats.nbi.dk -- -- Web...: <URL:(URL) -- ---...--- (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Comprehensive meta-command list
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Gary Williams: (...) Yes, but I don't think they are well known anyway: 0 TITLE <description> is an alternative to just using the first line in a file for the description of the file. 0 NOFILE terminates a model in a MPD file (so does another FILE (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) Instead of asking the user, the program could first try to cast rays and then only if there are any faces left it asks the user. I've started writing my own converter and it worked correctly with the 'standard' bricks but had a few problems (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Comprehensive meta-command list
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I'm attempting to compile a list of all meta-commands...did I miss anything? Current (From the LDraw FAQ): 0 <description> If the first line of the file is a comment, it's assumed to be the description of the file. 0 STEP Used to indicate the end of (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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Steve Bliss wrote in message <37f4edd7.8510607@lu...et.com>... (...) are (...) rotated (...) thinking. (...) Possibly. I'm not to great when it comes to expressing myself. I think if an even number of mirror operations are performed on a part, its (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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(...) OIC now. I think. If an asymmetrical part is mirrored, it keeps the same shape, but is turned inside out. To get it right-side-out again, it must be re-mirrored. In other words, there's no way to produce left- and right-handed pairs of (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: CW/CCW, vertex sequence, co-planar, convex, (115kB)
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(...) Jacob: (...) Why? Having a negative determinate *should* turn subfiles inside-out. IMO. That's a useful function. Having programs checking determinates is not useful, and wastes rendering time. Steve (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files
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(...) We're it. So to speak. Steve (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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| | Re: Hidden surface removal, and vertex order in part/primitive DAT files [DAT]
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(...) 578 is compliant because it contains *only* subfile references, which have been verified to not mess up (C)CW-ness. But that doesn't mean the *subfiles* are compliant. It also assumes the compliant subfiles are oriented the way the author (me) (...) (25 years ago, 3-Oct-99, to lugnet.cad.dev)
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