What the heck are these things?

The files presented on this page are LDraw-compatible parts that approximate some of the pieces produced by various competitors in the construction toy brick market.  Using the same .dat format as official LDraw files, these pieces can be incorporated into one's existing parts library, allowing the user to create models with a range of unofficial parts.

Well, that depends.  For a host of reasons, some people reject non-LEGO bricks as inferior, undesirable, our just plain crummy.  If you don't care for competitors' brands, you probably won't like the clone dat-files.  If you like clone brands, and especially if you've wanted way to model files using clone bricks, then I hope these are just what you've been waiting for.
In general, I would characterize the clone dat-files as good enough, and certainly better than nothing.  So far this has been a fairly casual project for me, and I haven't sought or received much outside aid.  As a result, some parts lack the polished perfection of many of the official  LDrawpieces.  Specifically, there is occasional overlap between cylinders, for instance, and certain pieces have poorly-rendered undersides.  These may be addressed in future updates, depending on overall interest.

Yes, except insofar as some clone brands use different conventions of size.  The standard 2x4 brick is 24 LDraw Units (LDU's) tall, while a 2x4 plate is 8 LDU's tall.  Some clone brands include parts that are 12 LDU's tall, while other brands have parts that are 10 LDU's tall.  Another issue of compatibility pertains to the positioning of the part relative to the x-y-z rotational axis; the default  for official LDraw parts is to position the topmost surface of the part at y=0.  I went in a different direction, so that the bottom-most surface of a part is at y=24.   There are a few exceptions, such as certain windscreen and hinge pieces, but for the most part I tried to be consistent.
Beyond these minor concerns, all of the clone.dat's are generally compatible with the official elements, but some may require careful manipulation to get them to match up correctly.

So far the clone library includes parts produced by MegaBloks, TYCO, Block-Men, Best-Lock and Byggis.  I should say outright that these files are not endorsed by LEGO nor by any competitor's brand.  Because of this, the name of the brand from which the part was modeled does not appear in the part description, since that might imply an endorsement when none exists. For that matter, I'm fairly confident that these companies don't even know (or care) that the parts exist, so no endorsement appears forthcoming.  Moreover, certain parts are common to nearly every construction toy brand, so the attachment of a specific name would be arbitrary in any case.

Since this project is an effort to provide as many clone dat's as possible, it seemed reasonable to model parts similar to those already found in the official library, as long as those parts are also manufactured by clone brands.  In addition to completeness, this allows the user to build models using only clone dat's, rather than mixing brands.  Finally, it was pointed to me that, when rendered at highest quality in POV-Ray (using Lars Hassing's fantastic L3P dat-to-pov converter) models would feature the "LEGO" logo on official elements but not on unofficial ones.
Even worse, a clone part using the stud.dat primitive would show the "LEGO" logo on a non-LEGO brick!  Many, myself included, may find this undesirable, so at John van Zweiten's suggestion I made the studc primitive that will render just fine but won't include the logo. Take a look at a sample, and see if you can distinguish the official stud.dat from the unofficial cstud.dat.  Rest assured that even the clone parts that are basically identical to official LDraw elements were written from scratch, rather than simply renaming existing parts, and each clone part has small but real differences from its official counterpart in order to demonstrate that the clone was written from scratch.
Another point to be made is that, in general, the clone parts are oriented perpendicular to the LDraw standard.  This serves both to distinguish the clone parts at a glance and to demonstrate further that the parts aren't simply stolen and renamed official elements.

If a clone part is substantially identical to a part in the official LDraw library, then I've added a "c" at the beginning of the official name, so that the clone 2x4 brick is called c3001.dat.
If no direct analog exists, I use a format based on the size of the box necessary to surround the part, in increments of 1x1 bricks.  A part that is 1 brick wide by 2 bricks tall by 3 bricks deep would be named c010203a.  The "c" indicates that the part is a clone, while the "a" distinguishes the part from others with the same basic dimensions, such as c010203d.  Obviously this name format is limited to 26 parts with the same dimensions, so I'll have to come up with something else before too long.
Finally, if several pieces are most commonly used in combination to produce a single whole, these pieces will all share similar names.  For example, c020504b and c020504d combine with other parts to yield c020504a.

Simply unzip clone001.zip in your LDraw directory, and the parts, sub-parts, and primitives will wind up in the correct directories.  Then run Makelist.exe or whatever library manager you use.  All the clone part descriptions begin with the word CLONE, so if you sort by description they should all be in the same place in your parts.lst file.

Included in the zipfile is noclones.bat, a ridiculously simple program for deleting the clone.dats, including primitives and sub-parts.  You'll need to rerun Makelist again afterward to generate an accurate library listing and to verify that the clone.dat's are gone.

Tore Eriksson has been kind enough to allow me to include in the clone.dat library several parts that he created, and by his own assertion those parts are public domain, free to be altered or modified as the user sees fit.
All other parts are expressly NOT public domain and may not be altered without prior written approval of the part's author.

Absolutely not!  The official LDraw parts library is exactly that--official.  The clone.dat's are non-LEGO-based and are therefore by definition unsuitable for the official LDraw canon.  A disclaimer appears in each dat file to underscore my intent that these parts never be submitted to the official parts library.

I'd be happy to accept parts written by other people.  For now, I don't have any formal voting process in place, since this has been an almost entirely solo venture.  Therefore, at the outset I'll be reviewing any parts submitted to me and accepting or rejecting them mostly on my own.  I'm not an ogre, though; if a part doesn't have any glaring errors I'll probably be quite receptive.  I reserve the right to make small modifications such as orientation and naming format, but overall I won't make changes to the basic part itself.
I consider these clone dat's to be the "official unofficial" LDraw parts, such that these represent the "official" clone library.  However, there's nothing to stop anyone from creating an "official unofficial unofficial" part library; in fact, I encourage it!

Criticisms are welcome, as are kind words of support.  I'm aware of a number of shortcomings in the parts, but I wouldn't be surprised if there are more that I didn't spot.  Let me know if you find any mistakes and I'll post corrections, including, if you'd like, a line in the dat file giving you credit for spotting the error.
Send criticisms, gripes, and praise to me here .  (Part submissions can be sent there as well)

Soon I'll make it more visually appealing. I was in a hurry to get the clone.dat's posted, so I just threw this FAQ together to field the most basic questions.

Uh, it's kind of off-line at the moment.  Upon reflection I found that a few of the parts were wholly unsatisfactory, so I've temporarily removed the clone libary from the page.  Once I get the details smoothed out I'll repost the updated file.  Sorry for the delay...
 

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 Except where noted, this page and all contents thereof are copyright 2002 and may not be modified without the owner's prior written consent.  Excepting those  written by Tore Eriksson, files contained in the clone.dat library may not be modified in any way but may be freely distributed so long as credit is given to the authors of the parts.