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Subject: 
LCAD02?
Newsgroups: 
lugnet.cad
Date: 
Mon, 15 Jan 2001 20:34:34 GMT
Viewed: 
735 times
  
Current De-facto LCAD(97?)standard (ie L-Draw/MLCAD)is lacking in some areas
namely:
  No suppourt for curves or curved surfaces natively.
  No Text postioning.
  No Texture Mapping ( Although Leocad does suppourt it and imports LCAD .DAT)

Rather than have incompatible extensions I thought it might be an idea to
standardise upon an updated DAT format to suppourt these.
Some of my ideas for this are below....

LCAD 02 - Very inital Ideas.

Filename extension change to .LCF -LCAD format
and mime-type of ?

Line types:
----------------------------------
The Line types are as follows.

LCAD 02 Line Types.
Line Type 0  : Comment/ Meta - AS LCAD(97) with additonal Meta commands.
Line Type 1  :  Part inline? AS LCAD(97)
Line Type 2  : Line AS LCAD (97)
Line Type 3  : Triangle AS LCAD (97)
Line Type 4  : Quad AS LCAD (97)
Line Type 5  : Optional Line. AS LCAD (97)
Line Type : - 6 Point.
Line Type : - 7 Enhanced Line.
Line type : - 8 Texture Map
Line Type : - 9 Sticker Map
Line Type : 10 - Arc
Line Type : 11 - Circle Sector.
Line Type : 12 - Circle Sector Clipped.
Line Type : 13 - Postioned text
14-120 <reserved>

Line Type : 119 - Camera ?- Ie viewpoint!!
Line Type : 120 - Fog/Mist/Blur area...
Line Type : 121 - Infinte Light.
Line Type : 122 - Light Source
Line Type : 123 - Celing
Line Type : 124 - Floor
Line Type : 125 - Sky
Line Type : 126 - Backdrop

Line Type : 127 - <reserved> - Possibly useful to flag deletions in editors?

Line Types with Top bit set are specfic to the parts/primitiive library in
use and are essentialy are a shortcut (line 1)

For LCAD02 - Lego(R) Parts Lib this shall be.
Line Type : 128 Subassembly. - NB This shall be common to all Libs.
Line Type : 129 Model.
Line Type : 130 Baseplate.
Line Type : 131 Minfig Head.
Line Type : 132 Minfig Torso.
Line Type : 133 Minfig Legs.

New Meta Commands
-----------------
0 BUILD CLASSIC/CSG..   Change between classic LCAD(97) consturction or CSG
contruction. NB This is dependent on BFC spec..

0 LINK <url>- Attach a URL to the group of parts,quads whatever added since
the last 0 LINK or beginning of file..  (Essentialy this could be a link to
an additonal model,sub assembly or link to a file of additonal information..)
If these parts are doubled cliked in viewing mode in a suitable enabled
LCAD02 viewr than a broweser will be callled to display the contents at the
URL specifed in <url>.

0 LIGHTING ON/OFF/AMBIENT - Change interpretation of Line types  121 & 122

0 QUALITY <num>           - Change Quality of rendering processing.. Will
cause some linetypes to be ignored until next 0 QUALITY.

0 SCRIPTED      - Indictaes that the next portion is writen in a scripting
format and not LCAD02.. This is to allow for conversion tool 'specials' and
LDS compiler scripts..
0 SCRIPTEND   - Indicates the end of a script.

Or would it be more sensible to allow a Meta command to group line types
command which had identifer names and then have META commands around it
setting the VARS?

e.g 0 USING X IS 0>100 IN 20
    0 USING Z IS 0>100 IN 20
    1 <X> 0 <Z> 1 0 0 0 1 0 0 0 1 stud.dat...
    0 RELEASE Z,X

But that does mean LCAD starts to look like FORTRAN ;-)

LCAD Parts Lib Structure.
-------------------------
LCADLIB\ - Top Level for all parts Libs. - Individual parts Libs stored
below this.
LCADLIB\P\ - Primitves common to all Part libs.

LCADLIB\Plugin\Created File\... - A directory used to stor file output by
various tools or plugins to an LCAD02 viewer/editor.

LCADLIB\LDRAW\P\       Primitves common to all L-Draw parts.
LCADLIB\LDRAW\P\STUDS\ All LDraw stud types...

LCADLIB\LDRAW\Parts\   All Current LDraw parts... Recomend This use
subdirectories identical to Partsref?

Also recomend LCAD02 use a Taxanomic naming scheme for parts.. Could be dir
structure although a Parte Registry might be a good idea!..

Note that they will be specifc directories in additon to Partsref for
.\Baseplates.   - Used by linetype 130   Lego(R) Baseplates...
.\ Minfigs      - used by linetype 131   Complete Minfigs..
.\ Minfigs\Heads- used by linetype 132
.\ Minfigs\Torsos- Torso Patterns used in constructing minifig torsos for
Line type 132

LCADLIB\LDRAW\Unoffical\ Ring fenced directory for non-approved parts or
devlepment work.

Recomendations for LCAD Editors...
----------------------------------
Suppourt for image processing plugins?

Plugins could be of various types:

Procedural construction-  Auto helpers for common part subassemblies.
Rendering systems-        interfaces to particular rendering engines
Conversion tools-         To aid saving and/or loading of objects from other
modellers or CAD systems.

I would also suppourt an LCAD automation interface or API... but not via
COM(I would prefer CORBA as this would enable co-operative LCAD projects :-) )

---

This is by no means a PROPER stansard yet but any comments are welcomed...

If explantory files are need to help clarify a point.. I'll try and write some.

And of course I'll need to find a site to host the LCad02 spec...(LUGNET?)

Alex



Message has 3 Replies:
  Re: LCAD02?
 
Farlie A <alex_farlie@hotmail.com> wrote in message news:G7815M.K6y@lugnet.com... (...) some. (...) Some good ideas to be considered - I just skimmed it, but it looked somewhat good to me. I don't have very much knowledge about the inner workings of (...) (23 years ago, 15-Jan-01, to lugnet.cad)
  Re: LCAD02?
 
Expanding info available... Exsting L_Draw/MLCAD is reffered to as LCAD(97) (...) LCF Syntax : 6 <x y z> Indicates a single point at cordinates shown (Intended for use as a means of specifying rotation and postional centers. with additonal meta (...) (23 years ago, 15-Jan-01, to lugnet.cad)
  Re: LCAD02?
 
Any support for animation? -Chuck (23 years ago, 15-Jan-01, to lugnet.cad)

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