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Orion Pobursky / $1 | |
| LDraw File Specification Describing Virtual LEGO® Bricks and Models Purpose 2 LDraw Files 3 Line Types 4 Line Type 0 4 Line Type 1 5 Line Type 2 5 Line Type 3 5 Line Type 4 6 Line Type 5 6 Colors 8 Meta Commands 10 Step 10 Write/Print 10 Clear 10 Pause 10 Save 11 File Type 11 Category 12 Keywords 13 Other Meta Commands 13 Purpose Describing LEGO® bricks and models in a virtual environment is a challenging prospect. In 1995 James Jessiman developed just such a system with is his LDraw program and file format. Since then the LDraw file format has grown to be the standard by which most create virtual LEGO® models. The aim of this document is to compile and consolidate James’s original file specification with the additions made since. LDraw Files Text Based All LDraw files are plain text based. Extension All LDraw files carry the LDR (default), DAT or MPD extension. All files in the LDraw Parts Library must carry the DAT extension. Every line of the file contains one command. Every command is independent of other lines. There is no line length restriction. Every command starts with a number, called a line type. The function and format of the line is determined by the line type. Line Types The line type of a line is the first number on the line. The line types are: * 0: Comment or Meta Command * 1: Part file reference * 2: Line * 3: Triangle * 4: Quadrilateral * 5: Optional Line If the line type of the command is invalid, the line is ignored. Line Type 0 Line type 0 has two uses. One use is a comment the other is as a Meta command. If the first line of a file is a line type 0 the remainder of the line is considered the file title. This overrides any Meta commands on that line. A comment line is formatted: 0 comment Where comment is any string Meta Commands A Meta command is a statement used to tell an LDraw compatible program to do something. There are currently many official Meta commands and almost as many unofficial Meta commands. In a Meta command, a keyword follows the line type in the line. The keyword must be in all caps. The generic Meta line format is: 0 command parameters Where: * command is any string in all caps * parameters is any string. Note that if a Meta command does not require any additional parameter, none should be given. For a list of official Meta commands, see the Meta commands section Line Type 1 Line type 1 is a file reference. The generic format is: 1 color x y z a b c d e g f h i file Where: * color is a number representing the color of the part. See the Colors section for allowable color numbers * x y z is the x y z coordinate of the part * a through i is a standard 3D transformation matrix. This represents the rotation and scaling of the part. * file is the filename of the file referenced. Files can be located LDRAWPARTS, LDRAWP, LDRAWMODELS, or the current file’s directory. There is no limit on how far these files can be nested. Line Type 2 Line type 2 is a line drawn between two points. The generic format is: 2 color x1 y1 z1 x2 y2 z2 Where: * color is a number representing the color of the line. See the Colors section for allowable color numbers * x1 y1 z1 is the coordinate of the first point * x2 y2 z2 is the coordinate of the second point Line Type 3 Line type 3 is a filled triangle drawn between three points. The generic format is: 3 color x1 y1 z1 x2 y2 z2 x3 y3 z3 Where: * color is a number representing the color of the triangle. See the Colors section for allowable color numbers * x1 y1 z1 is the coordinate of the first point * x2 y2 z2 is the coordinate of the second point * x3 y3 z3 is the coordinate of the third point Line Type 4 Line type 4 is a filled quadrilateral drawn between four points. The generic format is: 4 color x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 Where: * color is a number representing the color of the quadrilateral. See the Colors section for allowable color numbers * x1 y1 z1 is the coordinate of the first point * x2 y2 z2 is the coordinate of the second point * x3 y3 z3 is the coordinate of the third point * x4 y4 z4 is the coordinate of the fourth point Line Type 5 Line type 5 is a filled conditional or optional line. This draws a line between the first two points, if the projections of the last two points onto the screen are on the same side of an imaginary line through the projections of the first two points onto the screen. The generic format is: 5 color x1 y1 z1 x2 y2 z2 x3 y3 z3 x4 y4 z4 Where: * color is a number representing the color of the line. See the Colors section for allowable color numbers * x1 y1 z1 is the coordinate of the first point * x2 y2 z2 is the coordinate of the second point * x3 y3 z3 is the coordinate of the third point * x4 y4 z4 is the coordinate of the fourth point The optional line can be a difficult concept to grasp. The best way to demonstrate how they work is through a series of pictures. Say we have an optional line at the point below 2. The other points are 3 and 1. In this case the line would not be drawn since points 1 and 3 are not on the same side of the line below 2. Now say we have an optional line at the point below 3. The other points are 2 and 4. The line would be drawn since 2 and 4 are on the same side of the line below 3. In the case of the picture above the only lines that are drawn would be those below 3 and 7. This serves to “outline” the edges of the cylinder, which is the intent of optional lines. Colors Colors in LDraw are defined by a number. The allowable numbers are 1-16, 24, 32-47, 256-511. The numbers 1-15 are the core colors. They are: 0. Black 1. Blue 2. Green 3. Dark Cyan 4. Red 5. Magenta 6. Brown 7. Grey 8. Dark Grey 9. Light Blue 10. Light Green 11. Cyan 12. Light Red 13. Pink 14. Yellow 15. White The number for transparent equivalent of the core colors is obtained by adding 32 to the core color’s number. For example the number for transparent blue is 1 + 32 = 33. Colors 256-512 are dithered colors. Only line type 1 is allowed to use colors 256-512. Basically colors 256-512 are the combination of two of the core colors. The way this is accomplished is: color = (color 1 * 16) + color 2 + 256 Example, if you want to combine Black (color 0) and Red (Color 4): (0 * 16) + 4 + 256 = 260 Colors 16 and 24 are special colors. Color 16 is the ‘current color’, whatever color the type 1 was that reference the file. Color 24 is the complement color to the current color. Line type 2 is typically color 24. The combinations are: Current Color Complement Color 0 8 1 9 2 10 3 11 4 12 5 13 6 0 7 8 8 0 9 1 10 2 11 3 12 4 13 5 14 8 15 8 The complement for the dithered colors is the complement for the first color of the two colors used to determine the dithered color number. For example: 260 = (0 * 16) + 4 + 256 the complement is the complement of color 0, color 8 Meta Commands The Meta commands documented here explain the behavior exhibited in ldraw.exe. For other LDraw compatible viewers refer to the documentation of the program you are using. Step Marks the end of a building step Format: 0 STEP The Step command causes the program to stop until the Enter key is pressed. Additionally a bitmap of the currently displayed model will be save to the LDRAWBITMAP directory Write/Print Displays a message Format: 0 WRITE message Or 0 PRINT message message is a string of any length. This message is not saved on any bitmaps. Clear Clears the screen Format: 0 CLEAR This command causes all previous drawn files and line types to be cleared. Any following lines are drawn as normal. Pause Pauses the drawing of a file Format: 0 PAUSE This command stops the further parsing of lines until the Enter key is pressed. Save Saves a bitmap of the current drawing Format: 0 SAVE Save a bitmap of the current drawing in the LDRAWBITMAP directory. This command does not cause the program to pause. File Type Indicates the type of file (model, part, etc), and if it is part of the LDraw.org Parts Library. Format: 0 LDRAWORG type update-tag or: 0 Official LCAD type update-tag or: 0 Unofficial type or: 0 Un-official type This meta-statement should appear as the last line of the primary file header. The first format (LDRAWORG) is the current standard for files in the official parts library. Older files still carry the second (Official LCAD) format. The valid values for the type field are: * Part * * Element – * Subpart * * Sub-part – * Primitive * * Shortcut * * Alias * * Cross-reference + * Model – * Submodel – * File – * Hi-Res Primitive –
Classifies a file according to a category Format: 0 CATEGORY categoryname This command is used almost exclusively in part files. A file can have only one category statement. categoryname can only be one of the following values: * * Animal * Antenna * Arch * Arm * Bar * Baseplate * Belville * Boat * Bracket * Brick * Car * Cone * Container * Conveyor * Crane * Cylinder * Door * Electric * Exhaust * Fence * Flag * Forklift * Freestyle * Garage * Gate * Glass * Grab * Hinge * Homemaker * Hose * Jack * Ladder * Lever * Magnet * Minifig * Minifig Accessory * Panel * Plane * Plant * Plate * Platform * Propellor * Rack * Roadsign * Rock * Scala * Slope * Staircase * Support * Tail * Tap * Technic * Tile * Tipper * Tractor * Trailer * Train * Turntable * Tyre * Wedge * Wheel * Winch * Window * Windscreen * Wing If a part file has no category command the category is assumed to be the first word in the file title. Keywords Adds additional classifying words to a file Format 0 KEYWORDS keyword keyword … keyword The keywords command is essentially a laundry list of words that further describe the file. Like the category command, this command is used almost exclusively in part files. The list of words after the KEYWORD command can be space or comma delimited. The words the list should not also occur in the file title. Other Meta Commands The following is a list of other Meta Commands. These commands are documented and maintained by the owner of their respective programs. The URLs listed are the last known good links to that product. This list is not intended as a limit but merely to prevent overlap. The following will be documented in future version of this document FILE name NOFILE BFC (CERTIFYNOCERTIFY)] [(CLIPNOCLIP) (CWCCW)] [INVERTNEXT] MLCad (http://www.lm-software.com/mlcad/) ROTSTEP (x-angle y-angle z-angle (RELADDABS) END) BACKGROUND <filename> BUFEXCHG (A-H) (STORE RETRIEVE) GHOST line GROUP n name MLCAD BGT name MLCAD SKIPBEGIN MLCAD SKIPEND ROTATION CENTER xyz “name” ROTATION CONFIG ID Flag ROTATION AXLE MLCAD SPRING MLCAD FLEXHOSE MLCAD RUBBERBELT LPub (http://www.users.qwest.net/~kclague/LPub/index.htm) PLIST BEGIN SUB fname PLIST BEGIN IGN PLIST END BI BEGIN GRAYED BI END LSynth (http://www.users.qwest.net/~kclague/lsynth/index.htm) SYNTH BEGIN (RIBBEDTUBE FLEXIBLE_TUBE FLEXCABLE RIGID_TUBE ELECTRICCABLE PNEUMATIC_TUBE FLEXIBLEAXLE FIBER_OPTIC_CABLE RUBBERBAND CHAIN PLASTICTREAD RUBBER_TREAD) SYNTH END SYNTH (INSIDE OUTSIDE CROSS SHOW HIDE) SYNTHESIZED BEGIN SYNTHESIZED END L3P (http://www.hassings.dk/l3/l3p.html) L3P IFPOV L3P IFNOTPOV L3P ELSEPOV L3P ENDPOV LDLite (http://ldlite.sourceforge.net/) COLOR TRANSLATE ROTATE SCALE TRANSFORM COLORNAME POINT MATRIX CMDLINE line |
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