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Subject: 
Re: More information on LEGO Digital Designer and other things
Newsgroups: 
lugnet.cad, lugnet.lego.direct
Date: 
Thu, 1 May 2003 21:32:17 GMT
Viewed: 
2025 times
  
In lugnet.cad, Jake McKee writes:
LXF is an open, (and soon to be) well documented format.

Yay!

This format can be
used by anyone for parts, models, or something else you might come up with.
There will be some amount of restriction on the usage, just like the LDraw
parts have (can't be used for commercial purposes, for instance).

Obviously the LEGO-supplied LXF parts will have some restrictions.  Do you
also mean that homebrew LXF parts would also have restrictions?  AFAIK, if
I create my own part in LDraw .DAT format, I can sell it.  I just can't sell
parts I download from ldraw.org.

I think it would be reasonable if the restrictions disallowed commercial
use of homebrew LXF parts which embody official LEGO parts (e.g., LEGO's
intellectual property), but if someone makes, say, a birthday cake in LXF
format, they should be able to sell it.  IMHO.

Which means if you want to make MEGAbloks parts, or anything else, then
you are welcomed.

Yay!  And K'Nex, Tinkertoys, Lincoln Logs, Anchor Stones, Fischertechnik,
Geomag, Roger's Connection, Modulex, Cuboro, Scalino Marble Runs, Zome, Zolo,
and Zoob?  Is it a general 3D description language?

If it's general enough, it might preclude the need for a Construction Toy
Markup Language.  :-)

If you wanted to make a part that looked like a birthday cake, you
can. You just can't sell parts made in our format or incorporate them in
commercial applications.

That doesn't seem fair, if the thing I'm modeling is my own design.

(I know there are several "exceptions" that may be
asked about, and I am already working on getting those questions answered.
I will be back with answers as soon as I can)

TIA :)

3+ years in the making, we consulted the fans as both a large group and as
individual conversations. The format is both a binary format and a text
(human-readable) format.

Yay text!

BTW, do you mean that an LXF file would have both binary and text sections
in the same file, or that the SDK can read/write LXF files in either binary
or text forms?

[...]
The SDK is a by-product of the DD efforts, and since we are only building DD
for Windows, the SDK we release will only be Windows. That being said, there
is no reason it can't be ported, since the SDK will be well documented.
Really all the SDK is going to be is a set of Windows DLLs. Now before
anyone strings me up from my toes, please understand that with such a very
small percentage of our LEGO.com users being non-Windows users, it just
doesn't make financial sense for use to develop DD for Linux or Mac.

But the imporant thing -- very encouraging, IMHO -- is that you'll allow the
SDK to be ported to Linux and Mac OS.  I'm very pleased to hear that.  I would
love to see an open-source version of the LXF SDK for Linux.

Will you supply a test suite so that authors of ported SDKs can test their
code against the official results?

I hope to be able to release the source code to these DLLs, but haven't
gotten final approval for that yet.

Do you think it'll be released under GPL or a license like Perl's, or would
it be a special LEGO license?  (Just curious...I don't think it matters to
much from a practical standpoint.)

BTW, do the DLLs in the SDK do any rendering or graphic manipulation or are
they primarily for importing, exporting, and internally manipulating objects
and object trees in the LXF format?

As far as the "certification process", there are still some details to work
out on how widely distributed the SDK is. So for the immediate term, let's
assume that we are taking about a undefined group of people. [Note: This is
for discussion only at this point, and may change later]. We will come back
to this later.

OK, sounds like, at least initially, the SDK source would only go to a few
people for the express purpose of porting the SDK to other platforms.  If
it's the case that LEGO doesn't want the whole world to have access to the
SDK, then I'm curious what it means for ports to non-compiled languages like
Perl and Python.

Curious also if the SDK is written in C or C++ or C# ?

- "Would LEGO like to see LXF replace LDraw someday? " - Only if you want it
to. For what it's worth, that's where we are putting our energies,

Aha.  I thought so.  That's one thing that hasn't changed in 3 years.  :-)
Not that there's anything wrong with that.

and if you like it then hop on. But if you (you meaning the community)
doesn't like it, then just ignore it and carry on with the LDraw file
format.

Well, there's a third option, and that's for the community to take what it
has learned from .ldr and .lxf, and develop a format that's superior to both
.ldr and .lxf -- both technically and legally -- but I don't think that would
ever get off the ground, since LEGO is probably being open enough with LXF.
:)

We know LXF
is a new unproven format, and that the LDraw file format has many strengths,
and may continue to have some advantages over LXF. We also know there are
some some shortcomings with the LDraw file format, which is why we are
attempting to create a next generation format. We're not trying to have a
battle of formats, just put our own new internal format out there for others
to use and if you like it, great! If you want to tell us what you don't like
about it or think should be changed, great!

I think that's awesome.  Way to go!

- "I expect we'll see a press release this summer touting the fact that
AFOLs have embraced the LXF format" - Only if you actually embrace it!

Ya, I fully expect that to happen, especially if we can get the cross-
platform issues solved quickly.  I think it's awesome that you'll document
the file format in enough detail that someone could write converters without
even having seen any LEGO source code.  This was probably my #1 concern that
I stated to Brad and Torben, with single-platform-ism being #2.

- "Will the documentation be complete enough that I can write, say, a C
program that converts LDraw parts into LXF parts?"  - Yes. Past that, we can
discuss more in detail soon.

Sweet.

[...]
- "I would *love* to be proven wrong" - Todd, hopefully I have helped you
out! Ha Ha!

Yay, thanks!

Please let me know if you have additional questions/concerns!

How easily will it be to convert .lxf parts into POV-Ray .inc files?  More
specifically, does the .lxf parts format define sophisticated 3-D geometry
primitives like spheres, cylinders, cones, bezier patches, blobs, etc.?  My
biggest technical concern about a new parts format -- one intended to be a
master format -- is that it ought to contain enough information to be
converted to multiple formats.  Again, obviously I'm not a parts developer,
but I'll be writing code for LUGNET that manipulates parts data for various
purposes.

What will happen to all the great 3-D libraries out there like LGEO, L3G0,
L3P, etc.?  I guess they would become obsolete, or be ported to LXF format?

I would assume that LXF handles colors as materials rather than just plain
colors, yes?  A black tire is a different "color" in LXF than a black brick,
right?  Will LEGO be releasing a full set of internal color IDs and color
names?  The color chart I made here <http://guide.lugnet.com/color/> I'd
love to update that with official color information.

Could someone at LEGO shed some light on the patent issue?  My sense is that
it's not something that will really affect us, but it would be nice to hear
that from LEGO.

--Todd



Message has 2 Replies:
  Re: More information on LEGO Digital Designer and other things
 
Lots of great stuff in here, please see comments (and <snips> below): In lugnet.cad, Todd Lehman writes: <snip> (...) Probably something like that. We are still working all this out. (Thus one of the reasons for the NDA that the LDraw developers (...) (22 years ago, 1-May-03, to lugnet.cad, lugnet.lego.direct)
  Re: More information on LEGO Digital Designer and other things
 
(...) For Perl (I think this is also true for Python) you would only need an API definition and a binary DLL or library for linux. The connection would be via XS (what I use) or SWIG. I done quite a bit of interfacing C to Perl. I think C++ is (...) (22 years ago, 5-May-03, to lugnet.cad, lugnet.lego.direct)

Message is in Reply To:
  More information on LEGO Digital Designer and other things
 
Wow! What a week for LEGO CAD! LPub going open source, another Java viewer underway, a Mac editor hits alpha, new version of LD4D, the LSC, MLCad on Linux, all this Digital Designers stuff... and I know I am missing something! Sorry for the delay in (...) (22 years ago, 1-May-03, to lugnet.cad, lugnet.lego.direct) !! 

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