Overall

Subject

• Create a game that simulates LEGO bricks
• Allow building and playing
  Building while playing and vice versa. Modeless, if possible.
• Construction
• All LEGO models can be built
• Many bricks available
  Probably import LDraw part database
  
• 6 degrees of freedom
  (LEGO Creator can't even tilt bricks (e.g. the usual car lights), which is a severe restriction.)
• One view only
  
  • A 3D view, in which editing is possible. It is assumed that this is the only view.
    "3D" here means real 3D, with free POV and hardware-accelerated.
    
  • Other views (top/side etc., to get the CAD-typical 4 views) are optional, and they may have different editing rules.
• Comfortable building
• Generally: Building should be as similar to real-world LEGO building as possible, but if the computer offers advantages, use them.
• Easy and fast selection of bricks to be inserted, even for newbies
• E.g. add additional meta-data about bricks ("brick database") and allow to filter/sort bricks based on searches on the meta-data. E.g.
  • Don't show any bricks with prints
  • Show only bricks that are contained in town models of the years 1990-1995.
• Count number of uses (by the user; in sets) of a brick type and offer a view sorted by decending popularity
  
• Show x most recently used bricks
• Favorites
• Other suggestions highly appreciated
  
• Easy and fast selection of bricks in the scene
• Select "blocks" of bricks, i.e. bricks that are connected
  
• Real-world contraints, e.g. collision and snapping, are modelled  and support easy building.
• No explicit "grid" should be necessary.
  
• Play
• Cars can be moved around manually from the outside
• Functional bricks
  Bricks can be POVs and move by themselves. Typical uses:
  
• Lights, flash-lights
• Movable parts (doors, hinges, turntables etc.) can be moved manually
• Wheels spin, when cars are moved manually (pushed)
  
• Electric, pneumatic
  
• Auto-bricks
• Primitive
  Endlessly spinning turntables etc.
• Model simulation
  Cars, planes etc. drive/fly
• at explicitly pre-defined routes or
• randomly at routes defined by bricks (e.g. street plates, railroad lanes)
  
• Steering
• View world from POV of minifig or other brick
• Comfortable movement of models (minifigs, cars, planes, trains,  horses etc.)
• Mindstorms
  Programmable
• Be independant of simulating LEGO. E.g. with an appropriate parts database and code for "functional bricks", Playmobil should be simulated.

Technical

• Scalable
• Scenes with 1 000 000 bricks playable comfortably, if hardware allows. 100 000+ bricks on a GeForce 2.
  (A complete Fire Fighter HQ has ~250 bricks, a boat ~80, a car ~30.)
  
• Refresh rate never under 30 frames/s
  
• Export-/Import to common formats. Directly or indirectly:
• DAT (LDraw)
• VRML (Web)
• LCA (Lego Creator), if possible
• Cross-platform
  Runs at least under Windows (95, 2000) and Linux.
  (I (Ben Bucksch) work on Linux.)
• GUI
  Use native (platform-standard) widgets.
  Do not use "kids-interface" with big buttons etc.. (Such an interface could be developed as an alternative, though, see below.)
  
• Open architecture
  Allow alternative user interfaces and extension especially of functional bricks.
  Keep parts of application as separate as possible.
• External helper apps
  Allow to comfortably start external apps, e.g. for ray-tracing.
  
• Open-Source
• Participation wanted. There's no way for me to achieve all of the above in a reasonable time-frame without help.
• Should the LEGO Group be able to create a commercial game based on our the code? I think yes.