Program Features

This page is mostly just for reference, it shows the features that I was able to find on each program’s website or elsewhere on the Internet.



  • Simple building, like LEGO® Digital Designer™
  • Useful for small-to-medium models (up to 2000 parts with old low-profile PC, over 3500 parts with newer PC)
  • In Java, fast and cross platform
  • Requires OpenGL, but can use entry level video card.
  • Use connection “snap” for easy building
  • Uses standard LDraw library
  • Update checks and notifications for program and connection database
  • Can load DAT, LDR, MPD and some other LDraw-compliant file formats (LCD, L3B, …)
  • Can save in LDR and export to MPD, including all custom blocks and unofficial parts
  • Support for flexible parts (experimental)
  • Support for building steps and player (experimental)

Program is in beta, some functions are planned.


Features for the latest, stable LDCad version (1.4b):

  • Windows and Linux support.
  • Multi-threaded (background) loading of parts.
  • Fast detailed real-time 3D rendering.
  • Basic part snapping on growing collection of (official) parts.
  • Integrated portable flexible parts support (springs, hoses, bands).
  • Script based animation.
  • Full MPD Support.
  • Part grouping.
  • Part ghosting.
  • Nested editing.
  • Relative grids.
  • Multiple file editing (open as many files you like).
  • Instruction stepping support.
  • Full undo/redo.
  • Copy/paste from to other LDraw software.
  • Highly customizable part and color bins.
  • Growing collection of example models.

Features for the latest beta LDCad version (1.5 Beta 1):

  • Detachable color and part bin windows, of which you can have multiple instances or none at all.
  • Extensive (optional) LDraw source window, with full nested editing support and a growing selection of line type property editing dialogs.
  • LDraw file reloading and external changes detection, and you can finally close files now.
  • Library part (shadow) editing, mostly intended for myself in order to add part snapping info so it is disabled by default and far from a full LDraw part editing solution.
  • Compressed (e.g. library support.
  • Single instance protection.
  • Loads of minor improvements etc., some of which are:
    • Better scrollbar handling
    • Bin window(s) can be used at a smaller width.
    • Part bin windows can render vertical or horizontal orientated
    • And many more tweaks and adjustments etc.
  • I also added almost 600 new part snapping files to the default shadow library including info for doors, windows, windscreens, fences, bars, antenna’s, plane parts, boat parts, minifig hats/hair and minifig accessories. Do note some (especially the doors and windows) need some additional work as I’m not sure how they behave/fit in real life any help on that is welcome.

LEGO Digital Designer (LDD)

Features (from Wikipedia):

The program features a palette of bricks and parts in different colors, that can be used to build any model imaginable, but only a subset of the bricks made by LEGO are available for use in regular mode, but the more comprehensive LDD Extended mode allows any brick to be put in any color, but these were not available through the Design byMe service. There is also a mode for viewing, in which screenshots can be taken and the model can be “exploded”. The third mode is where the building instructions are automatically generated, and can be saved as a .html file.


LeoCAD is a CAD program for creating virtual LEGO models. It has an easy to use interface and currently includes over 6000 different pieces created by the LDraw community.

It supports basic animation (via keyframing) and can export to 3DStudioMax, POV-Ray, and Alias Wavefront.

It has a cool little Minifig Wizard.



MLCad (Mike’s Lego CAD) is a powerful CAD system specifically designed to create building instructions as known from Lego, for your own Lego models and creations. MLCad reads and writes LDraw (a program of James Jessiman) compatible files but in an extensive window based environment. The program helps to create building instructions, which show step by step how to build a model.

The main features of this program are:

  • Easy to use
  • What you see is what you get
  • Full drag and drop support for adding, copying and moving Lego parts
  • Print your models and/or generate part lists
  • Create pictures of the steps for use in the www.
  • Create pseudo models from fractal landscapes or pictures
  • Minifig Generator
  • and much more

MOC Builder


  • Drag-and-drop building
  • Building with Connectivity
  • Undo, Redo, Cut, Copy and Paste
  • Loads both LDraw and LDD (Lego Digital Designer) models
  • Search parts by name and description either from LDraw library or BrickLink Catalog
  • Part Browser with customizable category
  • Supports all LDraw colors (as of 10/30/2014)
  • Find and replace (with color) parts within a working Set
  • Step browsing for building instructions
  • Automatic grouping
  • Overlap Check
  • Import a set as a model from local file system
  • Import a set from the Set Inventory of BrickLink
  • Export parts to BrickLink Wanted List
  • Calculate price of model based on BrickLink market price of the parts
  • +Connectivity Editor

MOC Builder is an open source, free software.

SR 3D Builder


  • Looking at some video worths more than 1000 words
  • NEW Minifig / Pose editor to create and manipulate Minifig in your models
  • Support for PowerFunction and Mindstorm electric cables
    Improved flex part management
  • Support for Piston – Rod mechanism
    Support for Linear Actuators and Shock Absorbers
  • Animation Console to easily create and animate your technic models
  • Towball, HINGES and GEARS SUPPORT! Take a look to the Gallery  to see what I mean
  • Connection Solver for quick connecting hinges and rotating parts
    Support for RACKS and steering
  • Belt Generator with real connections
  • Now with GROUP management
  • New exclusive MirrorBuilding features  for quick build of symmetric models. MUST TRY !!
  • Enhanced instructions editor to easily modify the order in which bricks are loaded in your model and/or take photos while building
  • Complex gear driven hinges support (quadrilaters deformation and steering)
  • Great fully 3D building envinronment with reflection and transparencies
  • You will see your model during loading time and can pause for instruction steps
  • You can modify and save models (lDraw/MLCad .dat compatible format)
  • Fast selecting/moving/adding/removing you’ll never see in MLCad
  • Copy/Rotation/Deletetion/Color change of single or multiple brick. Undo/Redo functionality
  • Real connections detection, not always the same near brick positioning
  • Brick selection by Block (means that solid connected bricks can be selected at once)
  • Grid positioning to speed up positioning of pieces
  • Automatic and precise positioning and orientering of most bricks according to connection detection
  • Automatic detection of rotation axles
  • You can easily load model from other known programs: it supports the following formats:
    • .dat files
    • .ldr files
    • .mpd files (only a few metacommand are currently supported)