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What are the dimensions of a LEGO brick?
What are the real world dimensions of bricks? (starting with 1x1 brick) Plates? Studs? Does LEGO think of this in metric or imperial units or something else?

This image shows the dimensions in LEGO Units. 1 Lego Unit is 1.6mm (the thickness of the plastic wall).  In those units the stud's diameter is 3 (= 4.8mm).

+1 for Lego Unit is 1.6mm - thats the important part, everything else is based on this.

Here I clearly see what I've found by try-and-error - to connect vertical wall of bricks with vertically oriented long brick (with rails - https://bricks.stackexchange.com/questions/6316/what-is-the-purpose-of-this-plate-with-door-rail/6317) I had to have studs on the side of wall once in 5 bricks. 5 * height = 6 * width.

How much is the gap between bricks? Does this graphic take the gaps into account?

@posfan12 they are designed to have a flush fit

There has to be some play, otherwise it would be hard to wiggle the parts apart from each other.

@Joubarc's answer points to Robert Munafo's measurements showing an actual stud pitch of 7.985 mm or 0.015 mm (0.0006 in.).

One important note.  The wall thickness varies!   For plates and 1xn bricks, the wall thickness is 1.6 mm, as shown in pcantin's answer.  For mxn bricks (where m>1) the thickness is closer to 1.2 mm with little nubs aligned with the studs, as shown in bartneck's answer.

@pcantin - Upon further analysis I believe there is definitely a allowance for play.  None of my bricks are exactly integer width and length.  Unfortunately I don't have enough reputation to answer this question.  I measured 24 different bricks and plates.   I believe the linear dimensions for width and height are exactly 8.00 mm * number of studs - 0.2 mm.  When I apply this formula across my 48 measurements (242) I get a standard distribution of 0.016 mm.  It also explains the 5.831.8 mm measurement from bartneck's answer

This image from Brickipedia should sum it up nicely:

A plate is exactly one third of a brick in height (3.2 mm as in the diagram). In other words, 3 plates stack to match the height of a brick. This is useful to know if you're short on a certain size of brick, but have enough plates of the same shape and color to cover it in height.

While LEGO uses metric nowadays, you may be interested to know that the bricks they originally copied (and bought the patent for later on) were made in the UK and thus probably used imperial measurements (although dimensions are not specified in the original patent). You may want to search for UK patent 529580 or Kiddicraft to learn more about this. There may still be remnants of that English heritage buried deep in the LEGO legacy.
Also, when LEGO started, I'm not sure what their measurements or tolerance were at the time, but they probably weren't as strict as they are now, which may account for some oddities in the system. For example, the distance between studs has been measured as 7.986mm rather than an exact 8mm.

I found this synopsis goes a lot further than what was generally known after the Tyco trial. There is even a thesis written on the topic.

@ErikOlson either that site is gone completely(http://www.historia.com.pt), or there's a typo(http://www.historia.com maybe). https://www.historia.com/legos/clones/texts/kiddicraft.htm doesn't exist either though.  https://web.archive.org/web/20150908034033/https://www.historia.com.pt/legos/clones/texts/kiddicraft.htm might be the archived version.

I used LDraw long before I learned about TLG's official use of millimeters. At some point on my own I measured a regular baseplate as being (roughly) 10 inches wide. In LDraw one baseplate is 640 units wide. Thus originally (and I still do this today even though I know it's not correct) I visualized the LDraw system as having 64 units per inch, and a 1x1 brick being 5/16 inches wide and 3/8 inches tall (ignoring the gaps between bricks). 1/16 inches happens to be very close to 1.6mm.

The precise measurements with an easy to understand technical drawing is available here. A PDF with the all the dimension is available for download.

Why is its size 15.8 x 31.8 and not 16 x 32?

There needs to be a 0.2mm gap between bricks so that they can be stacked. Yes, in a virtual/ideal world, bricks could be exactly 16 x 32, but in the physical world, there are tolerances in production and friction when put together.

Got it after reading your blog post above, thanks for your wonderful work.

Robert Cailliau has summarized how dimensions of LEGO bricks derive from:

The base measure 0.8mm (that's where the 1.6mm already mentioned derives from)
The play measures 0.1mm (for additional space between pieces)
The height of studs 1.8mm

It looks like the number as the same as given in other sources, but there is disagreement about the height of a stud. I've seen the value 1.8mm (Robert), 1.7mm (Wikipedia) and 1.6mm (answers given here). Maybe the difference is because of the "LEGO" logo on top of a stud.

The stud height disagreement can be easily settled by examining a 1x1 headlight brick: The face with the headlight stud is inset by the 1.6mm base unit from the theoretical no-play boundary of the brick. If the stud was 1.6mm high, we should have no problem placing another brick in front of the headlight face. Even if the stud was 1.7mm high, the 0.1mm play would still allow this feat, albeit with a very tight fit. Experience shows, howerver, that we can't fit another standard brick in front of a headlight brick, indicating that the headlight stud (which is hollow, so no logo involved here) ha

Wouldn't the interior cavity and the knob need to have a clearance tolerance? Both the cavity and knob could not be 4.8 so either the knob is smaller or the side wall thickness is thinner to make for a larger opening. If you go by the graphic on Mr. Cailliau's website the side wall is 1.2 leaving a cavity of 5.4 based on the 7.8 overall dimension (8-.2=7.8). This leaves a tolerance of of .6 which is rather large. If you were to use Mr. Cailliau's clearance of .2 between mating parts the clearance diameter would be 5.2 leaving a side wall thickness of 1.3. Alternatively we could reduce bot by .

Archive of site: https://web.archive.org/web/20170116173744/http://www.robertcailliau.eu/Lego/Dimensions/zMeasurements-en.xhtml

These photos of side-by-side 2x4 bricks may be able to explain why people disagree as to the height of a Lego stud:

My Legos have definitely had different height studs over the years.

Lego had the moulds changed to metric.
From brightontoymuseum.co.uk website I learned that the stud width measures 4•87 or 4•88mm, so they are bigger than the 4.8mm space they go into, giving a tight fit & expanding the brick into the 0•1mm space around it.
Reading what is illegal for Lego, says Technic studs are not as tall, so going from a headlamp brick over them is okay when not so for normal bricks, as their studs are too tall.
The side walls, & so also from stud to the edge were 1•5mm, then bricks with thinner 1•2mm with ribs. As I found they fit to older bricks better than the other bricks do looks like smaller space.
On 1other website they found height to be under 9•6mm after measures stack of 100.

Hi Andrew! I tried to edit your post to make it better readable. Please review it and correct anything where I might have misinterpreted your intention.

Do you have references for your statements? Which museum website? What "one other" website you have in mind here? What is the source of change to metric?

Your statement about the technic bricks is incorrect or misinformed. Height of the bricks is the same, stud-height also if compared with other bricks with hollow studs (no lego logo...). The illegality issue is when connecting bricks with studs on the side (like headlight bricks) with the side holes in technic bricks. As the holes are 1/10th of a millimetre lower than the side studs...


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Does Lego market sets that were designed by fans?
My {son, daughter} read on a LEGO box that the set was designed by a LEGO fan. That is amazing! Is this common and how does my {son, daughter} get into that?
What sets were designed by fans so far?

What's the product number on the box?

You could use "offspring"

@Joubarc: I am tempted to put that in with my newly-earned edit privilege.

If you do that, I will no longer have sets. (ducks)

In addition of the already mentionned Blacksmith shop and the three first LEGO factory sets (5524 — Airport, 5525 — Amusement park and 5526 — Skyline, combined from the 10 winners entries of the contest), the following sets have been designed by fans:

10190 — Market Street was designed by Eric Brok. Eric sadly passed away a few month later.
10183 — Hobby Train was designed by a team of 10 fans who created 30 different models, all of which are buildable with parts in the set. The fans were Ben Fleskes, Christopher Masi, Holger Matthes, James Mathis, Jeramy Spurgeon, Mike Walsh Cary, Pierre Normandin, Reinhard Beneke, Steve Barile and Tim Gould. All of them high-profile builders, and the set was nothing short of fantastic.
10191 — Star Justice, designed by Chris Giddens, against 10192 — Space Skulls, designed by Mark Sandlin. These sets had less success although they were very versatile and allowed for countless hours of space building. They also heradled a comeback of Space themes, which LEGO hadn't been producing for a long time.
10200 — Custom Cars Garage, designed by Joe Evangelista, Joe Meno and Stephan Sander, again well-known names in the LEGO community.
10025 — Santa Fe Cars - Set I and 10022 — Santa Fe Cars - Set II were designed by James Mathis (thanks to Erik Olson for reminding me of these two)

Also, you have to keep in mind that the line between high-profile AFOL and LEGO designer is becoming very thin, and some people have crossed that line (Pierre Normandin, for example). As such, can't it be said that the sets they design now are created by fans? Designers are fans in their own right!
Also, in addition of the fans-turned-designers, LEGO does invite fans for workshops from time to time. Theire influence on 10194 — Emerald Night for instance is obvious, if only for them pushing LEGO to make big train wheels.
So, the line between fan and designer is blurry, and that's for the better.

I just remembered James Mathis' 10025 - Santa Fe Cars I and 10022 - Santa Fe Cars II two more fan designed sets.

Right, I had forgotten about these, I'll add them in, thanks.

Blacksmith Shop!!! I missed that.

If I recall correctly, it started in 2007 with LEGO's initiative called LEGO Factory, where fans were invited to compete in designing models using LEGO Digital Designer. The winners would then have their entries made into the very first fan-designed commercial LEGO sets.
Today, LEGO Factory is superseded by Design by Me. It follows a similar concept, except not in a competitive sense but a personal sense. This means you or your child can use LDD to design a set, share it, and even create custom box art for it, and have it ship right to your door, just as if you ordered a set from the LEGO online store itself.
I believe there were previous events that resulted in fan creations being marketed and mass-produced, but models created in the Factory competition and Design by Me initiative are not mass-produced.

As for what mass-produced sets were made by fans so far, I know there are a number of them (I believe a couple of building/architecture sets) but I can't remember their names or product numbers right now.

Set 3739 Blacksmith Shop was created by adult fan creation by Daniel Siskind, and was marketed by Lego in 2002. It was the first in the My Own Creation series.

Lego Cusoo is a website where you can upload pictures of your creations, and if they get enough followers,votes, they can be made into official set by Lego. (The current requirement is 10k votes)
The first model mass produced was the Shinkai 6500. To date, several more models have been released, including the Hayabusa satellite, a Minecraft set, Back to the Future, and the Mars Curiosity rover.(in order)

Shinkai 6500

The Lego Design byMe program offers the opportunity to design, build, and purchase custom Lego sets by utilizing the Lego Digital Designer software.

The main Design By Me programme is shutting down on 16th January 2012 apparently: http://toysnbricks.com/lego-design-by-me-closes-on-january-16-2012/ The homepage of DbM is also announcing this at the moment.

A shame... that note wasn't there on the DbM page last week. With luck, Lego will improve the concept and come back with a better offering.

Nope, the announcement was along the lines of "It was too complicated for kids to use. We suggest you use Pick A Brick, or our "Hero Factory Recon" service. Fixing it will make it too expensive" :(

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Does the LEGO Group condone war toys?
What is the LEGO Group's position on war toys? Other brands make tanks and army stuff. I noticed LEGO sets include more realistic guns in the Star Wars range than they used to. What's up with that?

Kind of.
From the LEGO Group's Corporate Responsibility report:

Guideline for weapons and conflict in LEGO experiences
A large number of LEGO minifigures use weapons, and are – assumedly – regularly being charged by each others’ weapons as part of children’s role play. In the LEGO Group, we acknowledge that conflict in play is especially prevalent among 4-9-year-old boys.
  An inner drive and a need to experiment with their own aggressive feelings in order to learn about other people’s aggressions exist in most children. This in turn enables them to handle and recognize conflict in non-play scenarios. As such, the LEGO Group sees
  conflict play as perfectly acceptable, and an integral part of children’s development.
We also acknowledge children’s well-proven ability to tell play from reality. however, to make sure to maintain the right balance between play and conflict, we have adhered to a set of unwritten rules for several years. In 2010, we have formalized these rules in a guideline for the use of conflict and weapons in LEGO products. The basic aim is to avoid realistic weapons and military equipment that children may recognize from hot spots around the world and to refrain from showing violent or frightening situations when communicating about LEGO products. At the same time, the purpose is for the LEGO brand not to be associated with issues that glorify conflicts and unethical or harmful behavior.

Page 26 of the 2010 report.

What about LEGO Halo? I don't see it on their website but the LEGO logo is written on some LEGO Halo models (Halo as in the MA video game)

@annonymously The Halo sets are made by MegaBloks, a "compatible" brick construction toy company. Have you got any links to LEGO branded ones? But either way they'd be covered by the "avoid realistic weapons" bit.

The SMG is pretty realistic in my opinion, but maybe it really is just megablocks.

The stuff I could find is all AFOL made and generally uses weapons from BrickArms, a 3rd party creator of "realistic" weaponry. Indeed, TT Games stated (when the April Fools of the LEGO Halo game was doing the rounds): "'Halo' is not a game that is age-rated for young players, and it's not appropriate for us to sort of recruit people into that experience.".

Their position has shifted over the years, in response to changing attitudes as well as commercial pressures, and the rising age of LEGO enthusiasts!
Originally LEGO bricks were only available in bright primary colours e.g. red blue and yellow, with the conspicuous absence of green, aside from baseplates. It seems quite likely that this was a deliberate attempt to prevent people from building tanks and military vehicles which in Europe were generally painted green. The creator of LEGO was known to be a pacifist and have strong opinions on the issue.
I remember that when the Pirates series came out in 1989 they were the first sets to include pieces that were explicitly firearms: muskets, pistols and canon. The Pirates series was also the first to include non smiling faces, allowing figures to show more emotion, including anger. Although LEGO castle sets had featured weapons a decade earlier, the wide smiles on faces of the knights and guards suggested a lack of aggression.
Space sets have always had some ambiguity between what is a weapon and what is a scientific instrument, though the same trend is observed toward more conflict in later sets. Competition with other brick toys which feature military sets as well as movie tie-ins have caused conflict/aggression to be a major feature of many LEGO sets made more recently, which is probably what triggered LEGO's shift in official message on the subject, as detailed in the corporate responsibility report linked to above.

is there any citation for the claim "It seems quite likely that this was a deliberate attempt to prevent people from building tanks and military vehicles"?

well, I can find a LEGO exec repeating this on camera in this video at 8:36 -- Jorian Murray "Lego Ad Exec" says "the founder was a pacifist and he absolutely did not want LEGO to be used for wargames, and that's why when it was originally launched, they just worked with few primary colors." Not totally happy with this source though.

Some Space sets before 1989 included parts that could be interpreted as sci-fi weapons (blasters, phasers, etc.), but that could also be interpreted as flashlights, telescopes, cameras, or other devices that astronauts might carry in space. What these parts were not, however, was realistic - you had to use your imagination to figure out what they were or could be, rather than just look down and say "oh, that's an 18th century European pistol".

"corporate responsibility report" is a dead link now :/

I believe that war sets have not been allowed from day one at lego, with the oft-quoted reason that Ole Kirk Christiansen did not was to reduce war to a 'state of child's play.' He was also reportedly a pacifist, and I have found a source stating that while lego may produce generic gun pieces, they will never directly model a contemporary gun, or likewise produce a set of one.
As stated (I think) in the 'Ultimate Lego Book,' Christiansen made sure that bricks in 'army colours' (i.e. green, brown, and olive green) were not produced. This changed later on however, when various sets required these colours, of course.
Hope this helps!

While the current plastic Lego "guns" are generally more tame (blasters, pirate pistols), that was not the case with wooden toys from the 1940's including this machine gun from 1945.  It's about 18" long and makes a rat-tat-tat sound when turning the crank.

Nice catch, where did you find that?

While I found this photo online, I actually own one of these.  Mine is a bit nicer, not nearly as worn.

LEGO has always been a bit iffy on it's stance towards war related sets, which might be part of the reason most custom part makers specialize in realistic guns.
Being primarily a children's toy, they had shied away from depicting tanks and battles in the beginning. It might be said that as popular culture in general had an easier stance with "playing war" (video games were probably a big part of this), LEGO also eased it's policy. I think the fist time LEGO sets included toy guns for mini-figures might be it's Western theme in the late '90s.
There might have been laser blaster type guns earlier than this with the Space and Star Wars themes. Now it seems that with Indiana Jones and other movie licenses they have obtained, Lego is again allowing their sets to be portrayed in a more violent manner.

No, already the pirates (and the blue-white or red-white anti-pirate forces) had cannons, pistols and rifles, and this was in the early 90's (or even late 80s).

@PaŭloEbermann: True, but they had historical weaponry of the kind that can be seen in any museum of history. More modern-looking pistols and rifles were introduced with the Wild West theme, and these were re-used in the Indiana Jones sets - however, then combined with vehicles that could pass as contemporary military for the first time, and also complemented with a more modern-looking gun accessory.

Even some of the classic sets had castles/knights with weapons, though most minifigs were decided in the non-violent category (astronauts, etc.).
As other posters have noted, many of the new licensed sets (Star Wars & Indiana Jones) are more violent, though often in a fantasy setting.

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Which BIONICLE set did this mask came from?
I just unearthed a rather wealthy stash of semi-rare Great Kanohi masks. Never knew I collected them! Anyway, among them was this clear transparent Kaukau (Great Mask of Water Breathing):

You may recognize this mask in transparent blue as worn by Toa Gali and some Ga-Matoran (notably Hahli) on Mata Nui.
But what stumps me about this mask is the fact that it's not blue; it's colorless. I've looked in Peeron but it doesn't list this as one of the colors it occurred in.
Does anyone know which BIONICLE set this mask may have come from?

I found the answer while I was writing this question, but I'm posting question and answer just for dibs on the bionicle tag ;)

The Peeron page for that mask I just linked to lists the part number as 32571. I do a search for the part number, and come across the Brickipedia page for that part. Scrolling down, I find the source:

Transparent:

8525 Masks (random)
8530 Masks (random)

Apparently, I found this mask along with the numerous bronze and silver Great Kanohi masks in one of those mask packs.
Fun fact: this colorless Kaukau was designed to be wearable by Toa Kopaka, and possibly also the Ko-Matoran. The Toa is known to have had this mask equipped in BIONICLE Chronicles 1: Tale of the Toa, but it's not entirely clear if this is part of the canon. There aren't any named Ko-Matoran with this mask as far as I know.

Feel free to keep custody of the tag all by yourself :-)


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Why do some sets have two different numbers?

Possible Duplicate:
Why did Lego use the same number for two different sets?

For example, 324 Ricky Racoon on his Scooter and 3605 Ricky Racoon and his Scooter appear to be identical in every way but the set number. So why did Lego use two different numbers?

My first Technic set (and last LEGO set before the dark ages) was the 852 helicopter, which had number 954 in the US. http://lego.wikia.com/wiki/852_Helicopter

The two questions are different. This one is "one set, two numbers" while the other is "two sets, one number".

In some cases, there were different numbers for the USA and the rest of the world, but I don't know if that's the case with Ricky Racoon.
LEGO also extended from a 3-digit numbering to a 4-digit numbering around that time, so maybe some sets were renumbered. At the time, LEGO didn't seem to care that much about set numbers (and as you've noted, reused some).

The Space sets also released first in North America in 1979 while Europe got Castle. The Idea Book 6000 came out in 1980 depicting the full range to both sides.  In 1981 the distribution crossed over after Castle had test-marketed in a few cities in the US. The Castle sets like 383 Knights Tournament got new 60xx numbers assigned at that time too.


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Why did Lego use the same number for two different sets?
For example, Ricky Racoon on his Scooter from 1979 is a completely different set from House with Garage from 1996, but they share the same number (324). Why did Lego recycle numbers like this? Do they contunue to re-use old numbers?

I recall someone asking this to a Danish employee at a public event in the US around 2003. In a very humble voice the LEGO employee simply said "We forgot." LEGO employees were admitting before that to using brickshelf for old instructions because they didn't have digital company archives yet.
It's possible they knew about the numbers and saw no problem with reusing the retired number. It's we obsessive fans that are the problem! When I was a kid, making my first LEGO master catalog, I was upset to discover 540 had been reused, for Swiss Villa, 1973 and Police Units, 1979 (before they assigned it to Basic Building Set, 1985. Argh!)
You can find many examples with this Peeron search Change the -2 to -3, etc to find more layers. Open a set, then edit the URL to -1 to see what it clobbered (sometimes Peeron has the newer set inventoried first as -1.)
So you can see how they are still doing it. But mostly it is done to impulse items, promos, basic bricks, and non-brick lines. I can't find a core set bumping off another set number after 2000 (see Scorpion Buggy for example.) Maybe they have stopped after that?

I'm fairly confident they try to avoid it nowadays, but as you say, at the time they simply didn't care.


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How many minifigs have actually flown in space?
I want to know how many have been to space (they don't have to have returned.)

In space, but no minifig (in german): http://it-republik.de/jaxenter/artikel/Java-goes-to-space-0092.html

There was some LEGO on STS-134 mission but I have not find info about minifigs. Also I have not seen any report about LEGO actually been used during the mission. Just the press releases saying that LEGO will be launched. Anybody knows more?

Actual Minifigures In Space
There have been a number of videos posted from the ISS mission, where we can clearly see one of the astronauts (Satoshi Furukawa) on the station holding a model with some minifigures:

On the Gallery Pages they list out "Working and living in space - This is the LEGO models shown in the videos"
In the shots there are there are at least 7, if not 8 minifigs (assuming that each hair and face is part of a complete minifig, rather than having the bodies reused for the shots):

This appears to be the first time actual articulated minifigs have officially gone to space.
In November 2021, The LEGO Group announced that two further minifigs would be travelling on the Artemis I launch as part of their Build to Launch: A STEM Exploration Series.

A Romanian named Oaida Raul sent the Lego Shuttle [bs:3367] up on a weather balloon to "the edge of space" on 31 December 2011, but hasn't released actual figures of the altitude reached:

2001: A Brick Odyssey

Two Canadian Students sent a Minifigure up to the stratosphere in January 2012, high enough to see the curvature of the earth, which can be seen reported on the Toronto Star's pages:

Minifigure Statues
Before then the closest thing to a minifig officially sent to space are the three custom built aluminium Minifigure statues that went up on the JUNO space craft this year:

JUNO Spacecraft to Carry Three Figurines to Jupiter Orbit

The Roman god Jupiter, his wife Juno and Galileo Galilei
This wired article concludes:

This unique project has put a smile on many Nasa and Lego employees' faces and stirred up interest from other state space agencies, as well. Will LEGO minifigs take another trip in space soon? Time will tell. But until that day, keep an eye on the sky for the fastest moving toys in the universe.

LEGOSpace.com's insistence on not supporting deep-linking fails me, but if you go to the Education Blog and scroll to Thursday, August 04, 2011

LEGO® Minifigures on a mission to promote space research
Three LEGO® Minifigures leave earth on the Juno deep-space probe today on a five-year mission to Jupiter to broaden awareness of the importance of planetary research.

Pictures of Minifigures
Prior to these two missions, previous missions have been promoted as sending Minifigures to space when in fact what they actually contained were pictures of minifigures:

LEGO bricks and products have been on several space missions. The latest mission with NASA was in 2004 when two astronaut minifigures hitched a ride on the Spirit and  Opportunity Mars Exploration Rovers.

When in reality what happened was:

Today, Opportunity returned pictures from Mars of another three “LEGO Bricks” and Sandy Moondust, the second “astrobot” representation of a LEGO Minifigure.

They didn't say those were the first did they?

@ErikOlson, nope, but they made a big thing about it, Lego under wrote the project, and nothing in the press stated that it had been done before "These will join the following mini-figures in space".

Super old thread but wanted to contribute :) I'm an engineer with Blue Origin and I'll be sending up this minifig later this month on the New Shepard rocket!

Great photo!  Thanks for sharing this with us.  Responding to "old" posts on StackExchange is a good thing.  It isn't just a forum or message board.  Did you name the minifig?

according to this NASA-article: at least 3 - the minifigs of galileo galilei, the god jupiter and his wife juno.

NASA's Jupiter-bound Juno spacecraft will carry the
  1.5-inch likeness of Galileo Galilei, the Roman god Jupiter and his wife Juno to Jupiter when the spacecraft launches this Friday, Aug. 5 [2011].

Since 2010 there have been Lego sets on the ISS but no mention of minifigs officially manning the outpost.

Actually, I think the correct answer to that is "none".
While two Astrobots, Sandy Moondust and Biff Sterling were designed to follow the adventure of the two Mars exploration rovers, these only contained pictures of them, not actual minifigs.
So this leaves us with the three custom-built aluminium minifigs of the JUNO spacecraft, but considering these as minifigs is a bit of a stretch. To me, these are but statues of minifigs, not real ones. They aren't even yellow!

No minifigs on the ISS?

Not being yellow is no reason to exclude them from being Mini-figures ;) There are many "non-yellow" characters now, including non-licensed ones from the Minifigures range (Zombie, Werewolf, witch, vampire, etc.)

@ErikOlson - Not sure about minifigs - there's a video here of Duplo on the ISS: http://www.legospace.com/en-us/Videos/Default.aspx#354655

@Erik: not to my knowledge, but I could be wrong.

There are also some up in the ISS right now:
http://www.collectspace.com/news/news-010815a-lego-minifigures-space-station.html

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Has anyone made LEGO fly?
It may not be the ideal material. But has there ever been a LEGO model airplane with the ability to glide, under power maybe, or some other kind of successful lifting airship? Helicopter, blimp, kite, even rocket?  Sliding down a string doesn't  count. Has anyone produced any kind of limiting analysis for this problem?

Does it need to be LEGO-parts only? If so, good luck with that.

Mostly Lego will do. Video of Lego with solid rocket motor added on is also acceptable.

All the time... oh, you mean sustained flight, not just projectile...

That's not flight, it's falling. Model must generate at least some lift to win prize.

This (http://www.rcheliresource.com/video-lego-rc-helicopter/) is a Lego replica, scaled up.  Looks pretty cool.

@Erik flying is just falling and missing the ground anyway

What about hopping? I'm sure a hopping Technic model is doable, and that does generate some lift (ok, not much).

I've often wondered whether you could get a 100% Lego helicopter to fly (or at least hover). I suspect that it'd be too heavy if it needed to include the batteries (even rechargable ones), but if you powered it by a wire connected to a battery on the ground it might work...?

I bought a set of FlyBrix last year that work as a passable quad/hex/oct drone. They've made some custom arms to hold their motors, and built some studs into the PCB holding the electrics.

I recently made a machine that kinda flies.. but not really. you know those little machines that you pull a string and a thing flies up and hovers down? thats what I made, but I'm having a few problems. not enough speed. I have a gear box that almost has enough speed to lift the propeller in the air, but not enough. if I had a bigger propeller, or make my gearbox faster, it could work. and it's a hand crank. did not have any power functions pieces or anything like that. only basic technic pieces (Gears, axles, technic studded beams, and a few other parts that require no power). I cant seem to

Does the new 60248 Fire Response Helicopter count?

Non powered/motorized flight has been achieved
Bamboo copter
Anna Vuurzoon made a Flying machine using only Lego parts which uses a ripcord to propel a three blade propeller on a stick (see http://www.mocpages.com/moc.php/288875). I was able to duplicate her results, so can validate it does work. It is really a modification of a bamboo copter. The 2015 Ninjago Lego Airjitzu series
( Lego #70739, 70740, 70741, 70742, 70743, 70744) are bamboo copters and work on the same basic concept as Anna Vuurzoon's flying machine.
Glider design
Daron Williams (via Drat Glider) and Milan "grohl" Reindl from Czech Republic have both reported making working/flying Lego gliders using mainly Technic cross-axles components.  Both gliders travelled between  20 to 30 feet with the Drat Glider with the bigger wingspan going a bit longer.  The wing cross section is more or less flat (one stud tall airfoil) and acting more like an air sail (paraglider) than an airfoil. Williams uses Lego Plastic sheets from the Mars Exploration Rover Set to cover the wing (wing cowling). Plastic sheets is the lightest wing covering that can be used but Lego does not make very large ones. Reindl uses plastic from garbage bag and tape to cover the wing on his glider - this allows for a bigger but heavier cowling. I have made my own Lego glider using the plastic from Lego store bags as my wing canvas using similar construction techniques as Williams and Reindl . My preliminary indoor flying test validate the results by Williams and Reindl.  Milan Reindl is now a Lego Group junior designer (you can see his profile on Lego Technic Designer Profile).
http://www.mocpages.com/moc.php/1769
http://www.youtube.com/watch?v=3CQcCoZ9rcY
The Challenge:
Lego does not make a quality aerial propeller or water/hydrodaulic screw-prop with a fuel efficient power stroke. The aerial propeller design for an all-electric aircraft have already be optimized by the Radio control aircraft community and can be fitted to a Technic axle but modern aerial prop design need to run from 4000 to 10000 rpm and use poly lithuim batery packs and motors that run at higher current and voltage than the Lego power function components.
The Vuurzoon design takes a lot of torque/power to fly and uses the power that it is given inefficiently. The only thing going for the Vuurzoon prop design is that it has the most efficient rotor angle to create lift. The Vuurzoon design uses hand power instead of electrical power and thus avoids the low power limitation of Lego electrical motors and battery pack systems.  Lego motors without gearing don't go above 2000 rpm at their set voltage/current level and have a high weight to power ratio which is bad for flying. Going over an 8:1 gearing causes a Lego motor to lose so much power/torque that any propellers slow down due to wind resistance (even the most energy efficient  light weight two blade electrical propellers has this problem).  Lego motors can go a bit faster if pumped with higher current and higher voltage from a non standard non-lego power source (e.g. poly-Lithium +15V power pack) but many believe this will shorten the motor lifespan.  Lego Power Function electrical packs are also too heavy for flight  the lightest battery pack is a Li-ion rechargable pack which weights about 75 grams. The heaviest Lego battery pack is the AA battery pack with alkline batteries which weights 195 grams — which is enough to sink a two catamaran hull or a large single hulled lego boat.
Standard Lego bricks are too heavy for an heavier-than-air airframe. The lightest Lego parts that can be used as an air frame are the technic axles followed by the half width technic beams— both are only semi-ridge so some bracing is need if air frame rigidity is required. In order to get a battery pack light enough and with sufficient voltage levels to fly as part of the aircraft — Lego needs to have to Lithium polymer battery pack kicking out between 18vdc to 30vdc — at those voltage levels the mini hi RPM motors used on Quadcopters and helicopter toys can start to be posssible.
Analysis of other attempts
Lego Quadcopter
There are several efforts to use Lego to make the frame of a quadcopter and uses a non lego high speed lightweight motors, hi powered batteries, and electric propeller. The high speed  motors usually run at 3400 to 15000 rpm @ 13 to 30 vdc and are very light weight. In addition it is using a non lego Poly-Lithium power pack some output as high as 30vdc even with heavy current drains. Some are using a Arudino microprocessor like device for remote communication.
http://www.youtube.com/watch?v=DkrTJh0H1fs
http://robotsquare.com/2012/03/02/flying-lego/
http://tinkernology.blogspot.com/2010/08/lego-nxt-quadcopter-no-really.html
http://www.suasnews.com/2012/12/20276/drone-made-of-lego-takes-flight/
Lego NXT Blimp-Airship
A lighter than air Lego Airship which was made by The Lego Group for a European Lego show/convention — uses Lego education propellers (from the renewable energy kit) and standard Lego motors and power supply. Prototype (non-commerical, custom made) helium balloons are used to create a neutral buoyancy so that the propellers can create lift and push the airship forward.  The Lego airship (called the C5) was demonstrated in an auditorium/stadium with a very high ceiling (there is no wind of any kind that the Airship would have to overcome).
http://www.youtube.com/watch?v=GefwcBUioAE

Some Bionicle sets featured pre-made ripcord propellers as well - not sure that counts, though.

LEGO seems to be way too heavy and not aerodynamic enough to build a plane so the best bet would be to build a zeppelin.
There's a video on youtube that shows such a zeppelin where the nacelle is build with LEGO (not sure if it's pure LEGO, take a look at it at about 1:55 in the video).
Another, much simpler example using only 5 helium-balloons and a 9V-motor: youtube-video
After some more searching I found this video. A LEGO-model of a Bell-Boeing V-22 that looks like it lifts off and flies by the power of his own engine but is suspended by wire.
Conclusion: Flying lego is possible when you add some none-lego-parts - building a zeppelin seems to be really easy using some helium-balloons while building an aircraft without suspension is not possible (or at least: not if you plan to use LEGO-motors as they simply don't have enough power).

Looks cool, but I'd just be too darn afraid of losing my LEGO bricks. "It's not coming back down!!!"

just take an airsoft-gun with you and shoot the ballons if it goes to high ;) - everything comes down sooner or later.

That vid with the Bell-Boeing V22 is faked. The last shot at the end shows the setup, which I also think was faked. Sorry.

...wich is what i wrote: "looks like [it] flys [...] but is suspended by wire"

Some family built a LEGO quad-copter. Unsurprisingly, it uses non-LEGO parts. Also, the design might seem a bit weird and worst of all, it's glued (uuurrrgh).
But it does work and appears to be very stable, enough to provide a nice remote camera view.

Not a pure Lego solution, as it uses helium balloons for lift, but it is (mostly) made from Lego and also uses a Mindstorms NTX for control.
Article on engaget
Direct link to YouTube vidio

The Brick Experiment Channel on Youtube shows a Lego Drone that flies. It's built with a combination of Lego propellors, Lego Power Functions L motors, a Lego frame, and some non-Lego flight-control computer, radio receiver, and batteries.
https://youtu.be/wUVvQk7XLd4
This is a truly amazing feat, showing how deep knowledge of the Lego motors and technic gear ratios can lead to tricks nobody believed possible, such as flight or breaking steel. I didn't think it was possible until I saw this video. A pure Lego solution would have to replace the flight controller, RF recveiver, and batteries with something like a Control+ Powered Up hub, which has a tilt sensor, bluetooth, and batteries, but is so much larger it would almost certainly be too heavy to fly, not to mention not well suited to the task of maintaining level flight for a drone (I doubt it's possible with a stock Powered Up solution to control motor power levels quickly enough in order to correct flight direction, but I've been wrong before).

Try Using Foam wings, and if you have the money, you could probably add motors, you would just need a Fast motor and the smallest battery box. I have a science fair and I'm going to use foam wings, Check it out!!!

I'm surprised to see that nobody has yet mentioned Peter Sripol's functional RC airplane constructed from LEGO!
It's not a "pure" solution - the powertrain, electronics, and control linkages are all constructed from hobby-grade products, not official LEGO, some pieces were cut to size, and some non-LEGO components were glued or taped in order to secure them to the LEGO components, but the airframe itself was otherwise constructed from LEGO using legal techniques.
For those who might not be able to watch the video or are uninterested in viewing the whole thing, the fuselage is mostly Technic and 1xN plates, with Technic beams supporting the wings and control surfaces, which are constructed from baseplates, except for the vertical stabilizer, which is constructed from bricks. The plane itself uses a 3-channel control scheme (power, pitch, yaw) controlled by traditional RC hobby-quality servos, receiver, battery, ESC, brushless motor, and propellor.  The dimensions of the aircraft appear to be roughly one meter wingspan by one meter fuselage length.  The wings and control surfaces, being constructed of baseplates, are not true airfoils, and instead generate lift and pitch/yawing moments by airflow deflection, aided by the ample thrust of the powerful motor and large propellor. The plane appears to be very difficult to control and prone to stalls, spins, and fluttering, but it does fly, if only for a couple minutes.

I made a 100% LEGO flying machine. It's built from three parts:

Propeller number 30333,
An axle (female end) Technic pin (male end two spaces),
A three inch axle.

To fly it you hold it in your hands and slide them past each other spinning the contraption. The highest it's flown is about six feet, I've made other ones similar with different pieces but now this seems the most comfortable to spin.

I made a 6041 (https://www.bricklink.com/v2/catalog/catalogitem.page?P=6041#T=C) fly by putting it on a pin and blowing really hard - once you stop blowing it takes off, mostly right into your face, so be careful haha

http://www.youtube.com/watch?v=wpttq5IlPx8
no joke, this video is a flying pure lego helicopter.
he just uses a nxt/mindstorms motor
and the blades do have pitch so it makes sense for it to fly

yes, but there's a giant counterweight so it's not lifting the weight of the model, which is what the question is asking for.

It's definitely cool, but it doesn't really fly.


text:
How many spaceman minifigure variations exist?
I was looking at collecting all the different Spaceman minifigures.  So I'm wondering how many different types(styles) of Spaceman do exist.  Color variations is not necessarily but it would also be interesting to know that.
Note: Only astronauts (not robots & aliens)
So far I only have those three:

This would be a good question for a CW answer, as the list is managable but it's unlikely any single person would get them all.

Do you want astronauts, or everything including aliens and robots?

@Pubby8 Only astronauts (I'll edit the question)

I sometimes play with my Star Wars Clone Troopers as astronauts.

I know this is an old question, and also that you specify minifigs, but you may be interested to know there were maxifig astronauts in 1975's set #367 Moon Landing

A full list of space related minifigures can be found on Bricklink here as well as under the Town theme. If you count fantasy themes there are also many astronaut minifigures under Alien Conquest, Blacktron, Life on Mars, Mars Mission, Space Police, etc...
There is also the Spaceman from the 1st Collectible Minifigure series.

I hadn't thought about the town ones - good catch.

I can't find the Apollo figure in that list(site). Still looking...

@pcantin: That's under a the Discovery theme

Not sure if you would include the Futuron Astronaut or Classic Space Astronaut in this list (image courtesy of http://www.toplessrobot.com/2009/05/the_30_greatest_lego_minifigs_of_all_time.php?page=2):

I had several of these as a kid - I remember black, blue, yellow, and red variants.

They also used the following helmet variation in Series 1 of the Minifigures set:

I also have the limited edition orange Lego Universe Spaceman that can be seen here:

Neither of these came with backpacks.
There is also now the Minifigures "Galaxy Patrol" style spaceman which started appearing in Series 8:

This combined a new helmet with the much enhanced backpack/shoulder armour element.


text:
What kind of metal/alloy were on the old LEGO 9V train tracks?
LEGO's train tracks (the actual rail part) were made from some kind of metal alloy that does not seem to oxidize, and seems to have good electrical charateristics (low resistance).
Any ideas what this might be?

Just to put it out there, I have some old LEGO 9V train tracks that appear to have small oxidation spots on them. It makes the train run a bit unreliably, which does not exactly please my 6-year-old nephew.

Ooh, what colour are the spots? If it's steel, they should be  rust-coloured.

I'm not sure about LEGO, but Märklin, a company that specialized in building train models used simple stainless steel since 1982, chances are that LEGO did the same:

Stainless steel is relatively cheap
It doesn't oxidize (as the name implies)
The electrical charateristics aren't good, but you don't need a very good (and expensive) material like copper for something "small" like toy train tracks (Märklin shows that it works)
Märklin builT the electric "H0" trains since 1935, such an experienced company might have been a inspiring example when choosing a material

Like starblue said, nickel-siver might also be possible. Another indication of this speculation is the German Wikipedia entry wich says:

Die Schienenprofile von Modelleisenbahnen [...] bestehen mitunter aus Neusilber [...]

Translated: "the rail profile of model railways [...] sometimes consist of nickel-silver [...]"

Both sound plausible – good finds :)

Maybe nickel silver, which would be a suitable material. But I only found a somewhat indirect claim on the german site 1000steine.


text:
LEGO Safety: Known risks and how to avoid them?
I run an after school program that teaches engineering to kids, mainly Kindergarten through 3rd grade (roughly ages 5 - 9).  I'm trying to educate my coaches as to the known safety risks regarding using LEGO bricks, so that they can be forewarned and can take steps to avoid them.  I think reading about specific, known cases, would be most helpful, along with any non-obvious preventative measures.
Anything that applies to class-safety would probably apply to home safety, too.

When I asked this question, I was finishing up a blog entry on the topic, which incorporated some of the answers given here.  You can see the final article here: http://www.ascendly.com/page/lego-safety-how-not-to-choke-break-a-tooth-lose-an-eye-or-throw-out-your-back/

Also, wear shoes at all times.

The most obvious risk is swallowing parts, even though at that age it's probably less likely to happen. Magnets are the most dangerous, but LEGO has done a good job of hiding them recently.
Projectiles are also a risk, whether they are intended as such or not. Actual LEGO lauching machanisms (zamor spheres launchers, for example) can be quite dangerous and there's always an icon in the instructions to warn children of that risk.
Electrical parts can be hazardous, in particular if liquids are close. Although LEGO does a good job of protecting its parts (I've heard PF motors run wel even underwater), be particularly careful of mains adapters.
Spinning parts. It's fun, until you pinch you finger between two fast-spinning gears. Why do you think the saw blade first introduced with exo-force doesn't have a cross axle hole?
Pointy parts. LEGO tries to make them as soft as possible nowadays, or rubbery when possible.
And then there's the possible frustration of not being able to make the exact same creation that you have in mind.

Is the electric hazard a real and documented hazard, or more of a perceived hazard?  I'm just sort of wondering if the voltage is ever high enough to cause any actual damage.

Electricity is such a minor issue. Kids won't get hurt unless they strip the wires and jam them through the skin into their chest next to their heart.

Voltage is broadly unrelated to how dangerous electricity can be. http://www.darwinawards.com/darwin/darwin1999-50.html. That being said, Lego's conductive bricks are very carefully designed to avoid exposure to the current. Definitely be careful around mains adapters, but the standard conductive bricks probably don't require any more supervision than the launchers or old-style knight weapons do.

Note: the fact you can't easily electrocute yourself with LEGO voltage doesn't necessarily mean you can't make sparks or start fires or something.

Make sure the kids avoid separating pieces with their teeth. Give them some brick separator tools and teach them to use them.
Sharing is very important! You don't want another kid bopping someone in the head because they stole their piece. If you don't have enough of a certain piece for everyone then don't include that piece.
If using projectiles only use 1 missile at a time. Safer to go 1 at a time than having 50 at a time. Also remember that kids only need the "cannon" while designing, not the missile.

Never aim projectiles at anyone's face.

If possible, give the kids large, rimmed trays (or even the lids from storage boxes) to keep their loose elements in.
This will reduce the number of pieces that fall on the floor and get stepped, knelt or sat on.

I wonder how much of a risk there is to slipping on a brick?  Especially considering most school have those very hard floors.

My students often use a cafeteria tray.  I introduced them, originally, to just keep the mess confined, sort of anchoring the activity, even if not everything stays on the tray.  A tray has an added benefit of providing a hard surface for building on, useful with carpet.

I think this is a good tip, but not much of a safety issue.

@Pubby8: You have obviously never stepped on the corner of a Lego brick in the middle of the night.

A friend suggested this funny video on brick safety: http://www.facebook.com/l.php?u=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DCBhyskisVNM&h=pAQF-QzJqAQGn7AcJQeW_2ZCAg8-T_dznz6h4HuLprZTNJg

Direct link to above video instead of linking through Facebook, which is a privacy concern.

Never fire bricks towards another persons face. There are certain sets that provide mechanisms to fire bricks such as the Agents: Gold Hunt set. The missiles are rubber tipped to minimise damage.
If your school students are tasked with a project that involves projectiles I'd make sure they wear safety goggles, Especially if it involves non-lego parts or motors.

Don't lift too many bricks at one time.  Being slightly older, I find a bag full of bricks can actually get heavy.  I recently pulled a back muscle lifting a bag of 9,000 bricks.  Hmmm, need to lift with my knees!
Granted, most people won't encounter this problem, I'm just saying....

Why is this getting downvoted.  A down-vote without an explanation is very discouraging.


text:
How can I create synthetic imagery (rendering) of LEGO models?
I'd like to know how I can create computer imagery of my own models or existing models.
How can we do photographic quality or cartoon like images?

possible duplicate of Do any programs exist that allow you to build own LEGO plans?

Both Lego digital designer and Ldraw allow for the creation of CGI LEGO models. Additional software may be required for photo-real rendering

Zhaph, digital imagery isn`t covered with plan making.

You need:
Digital Designer (Or anything that can produce Ldraw files, there are some listed in this question)
Blender (Or another renderer that supports Ldraw)
Blender Script (This is necessary for Blender to read you Ldraw models)

Recreate your creation in Lego Digital Designer.
Export as Ldraw format
Import in Blender
Create & render Blender scene

(I haven't tried but it should work)

I'd tend to replace the first requirement by "a LDraw file, created either with your favorite LDraw editor, or exported straight from LDD". Pov-Ray works too.

I am surprised by the recommendation of LDD. LDD has a very limited part library, which shifts every few months. Surely LeoCAD, MLCad or the other myriad of real LDraw tools should be the starting point.

@dannystaple LDD has an extended mode that you can turn on using a config setting to access a much wider range of elements: http://www.eurobricks.com/forum/index.php?showtopic=53760

While the blender script sometimes works, the technique of importing an LDraw file into LeoCAD, then exporting it as either an obj or 3ds file and importing it into Blender has been MUCH more reliable from my experience. In the python script, bricks often get left behind, lack all of their verticies, or simply don't get imported. A massive contrast from the LEOCAD technique provided by PeterDC.

Since the "Design by me" product is to be removed by Lego, it makes a lot of sense to switch the config as the upload/pricing will be of little/no use again.

In addition to the other answers, the oldschool way using POV (in use before there even WAS a LEGO Digital Designer) still works.

Model your creation in a LDraw compatible modelling tool of your choice (such as MLCad) but there are other choices
Use one of several export programs (such as L3P) to create a POVRay compatible file
Add a few commands to move the camera to taste and run a render in POVRay.

All of the renders on my site, http://miltontrainworks.com, such as this one:

Taken from the MTW-5001-yg listing, were done this way.
You can read more about all the tools mentioned at the LDraw website.

The Studio tool from BrickLink uses the LDraw Parts library and has both the POV-Ray renderer as well as a "Photo Real" renderer baked in for some fairly realistic renderings of your models.
For example:
A selection of wheels and axles. You can see the logos on the studs of the modified 1x2:

Apple Macintosh Sample Model:

Apple Macintosh Sample Model with "UV Degradation" and "Scratches" enabled in Material Effects:

Here's a method you'll be able to use with the latest stable version of Blender, without any extra plugins or addons.

Build your model in LEGO Digital Designer and export as an LDraw file.
Import into LeoCAD, then export as a .obj file.
Import into Blender with the built-in .obj importer.
You can then setup the scene how you want.

Also, if you're just starting out with Blender, you may want to try an under-development, photorealistic renderer called Cycles, as you'll be able to get nice-looking images much more quickly than if you were to use Blender's default internal renderer. From 2.61 onward, Cycles is now another render engine option in all official Blender builds.
You may want to check out this superb introduction to Cycles.

Also, some beginner tutorials: http://www.blender.org/education-help/tutorials/getting-started/

Let me suggest Autodesk 3ds Max software or Autodesk Maya software for achieving this. You can find free bricks and models meshes right here. Additional information on lego visualization can be found on Okino's website.
Here is the example of a rendered still. Doing a manual simply involve making parts of the model visible/invisible and positioning the camera appropriately.

This model was rendered by flickr user bloggerknight using 3ds Max and the VRay renderer

While I like the render, there's only a limited set of parts compared to LDraw lists, and things like MLCad/LeoCad etc. really help with lining up the parts properly, but I've yet to find a decent workflow that results in sensibly sized models in 3DS Max - the imports from LPub for example were always rather tiny :(

you're supposed to model the missing parts yourself :) That make it a workflow that isn`t meant for all.

heh. True, but I'd rather spend the time working on my shaders and getting it to sit right on a photo background if I know others have produced a full set of models in something else ;)

with the peeron measured colors and the "Arch and design" materials, you can get photorealistic plastics that are perfectly matching reality. with a calibrated background, you could get a an image that no one could tell it`s 3D. (I am assuming you have all the lego parts properly modeled, with the studs and lego embossing)

Yep, I was using the Arch and Design materials, and the rest, but had had some difficulty getting the model to a decent scale if I recall correctly.

I believe LEGO does their boxes and manuals using Maya. I wanted to write about that but couldn`t find any publicly available information. Someone, somewhere has all the bits it takes :)

Yes, lots of references to it on EuroBricks, not much else. Although I think I could just make it out in one of the "behind the scenes" videos recently.


text:
What is the basis of purism in LEGO building?
LEGO purism is the idea that LEGO constructions should be made with only with official LEGO blocks with no modifications. Other bits of plastic, papercraft, metal supports, and so on are frowned upon.
What is the reasoning to why one might build using solely LEGO elements? Is there something particular about LEGO as a building toy to which inspires this way of thinking?

-1 This is subjective. If you want to be pure, be pure. If not, don't. If you're entering a contest then use whatever the rules are. It's as simple as that.

I'm not asking about whether one should be purist or not. I'm asking about the import of this philosophy. You apparently would answer "it's not important at all", and I encourage you to express that as an actual answer, although I'd appreciate it if you could provide more depth into your reasoning. Thanks.

I've edited it to try to have it focus on one question. I think some of what you want to know should be split into separate questions, although the one about other toys isn't really on topic.

I don't mean to ask about other toys; I'm wondering if there's something special about Lego (either as a company or as a product) that encourages or prompts this philosophy, or whether it's just kind of an obsessive-fan thing that happens to appeal to Lego builders.

By the way, being a zealot doesn't usually involve reason.

@Joubarc: absolutely. I didn't have "reason" in the original phrasing of the question. While reason may not be involved on the part of the zealot, there are often certain features of an idea or cause which tend to attract a passionate response. Another related question might be "What is it about Lego that attracts fanatics?" (especially in this particular way).

I guess I'll open a discussion on Meta later when I have a chance. This is actually an important part of Lego fan culture and there is solid answerable theory behind the a great answer (which we don't have yet).

http://meta.bricks.stackexchange.com/questions/91/are-questions-on-the-sociology-of-lego-fan-culture-on-topic

I'm not too sure how to answer that. I don't want to modify any brick whatsoever myself, save for the occasional eletrical wire cut, but on the other hand I don't really care what other people do.
Considering LEGO designers aren't purist themselves (Need this part in green? Ok, I'll paint a yellow one.), why bother? Why not cut your own baseplates to the dimensions you want, when you know LEGO produces them exactly the same way, by cutting large sheets?
Then again you have different levels of purism. Part modifications. Non-LEGO usage. Non-LEGO stickers usage. Brick printing. Brick engraving. *cough*Glue*cough*. MegaBloks. And frankly, to each his or her own.
What I can say however is why I'm mostly a purist myself, if that's of any help. I don't want to modify bricks, or use anything non-LEGO, simply because I feel it would be cheating. I see building as a challenge, and each challenge has its own rules and limitations. If the part I would need to build something does not exist, then I have the additionnal challenge of finding another way to build so that I don't need it. And that's the thrill I get from LEGO building: finding the right existing part to suit my needs.
But then again, I'm not purist enough to care about what others do. Sure, I'll point a finger at them, but it's all in good fun.
Of course, glue will get you more than finger-pointing. Heretic!

Joubarc, I'm watching you, glue is illegal on Lego!

I'd like to point out modifying minifigures using self-made props is ok to most. There are even shops that specialize in custom minifigures.

@jfyelle I thought I heavily impied I was against glue, actually. But that's also something LEGOland park designers themselves use (and not any glue, they use methyl-ethyl-cetone (orthograph not guaranteed) which literally fuses bricks together). So, to each his own.

I was joking - maybe I should put smileys :)

So I've been a LEGO purist all my life without realizing it (no third party modifications at all whatsoever).

There's no badge for that, unfortunately.

Is there something particular about LEGO as a building toy which inspires this way of thinking?

Of course. LEGO is reusable. It's high-quality, durable, and you expect it to last many years. You might keep a construction together for some time, but always with the potential of being disassembled and turned into something else. Modifications like painting, cutting, or gluing are no longer reversible. You only make these changes when you're sure you don't need those pieces in their original state.
Have I irreversibly modified LEGO? Yes: I've made small stickers, painted minifigs, or used a few bricks in a permanent decorative piece. Nor do I really feel I have to use only LEGO. I would add a paper umbrella, a cardboard backdrop, a styrofoam support—anything I was sure wouldn't harm my bricks. On the other hand, I don't think I could bear to glue or paint a whole structure. (That's what other building toys and strategies are for, like modelmaking, dollhouse furniture, or model railroad set construction.)
To me, construction of something too permanent would subvert one of the reasons I love LEGO. There's always a bit of hidden potential: I might need those pieces for the next thing I'm dreaming about building...

This IS a subjective question and answer, but here is my take speaking as someone who got a start with LEGO toys in the 80's it came down to this:

The minifigs for non-LEGO brands were terrible and incompatible! Nothing beats the lovable, quirky shape to the official minifigs. You often had to construct differently for the different dimensions of the non-LEGO figures, or toss them out.
Non-LEGO brands at the time would snap together with official LEGO pieces, but the fit was different: either too much or not enough friction.
At the time: LEGO had the dominant brand, therefore, most of your pieces were likely to be LEGO brand, so the fewer pieces of the non-LEGO brand would be annoying for reasons 1 & 2.
LEGO was the original brand. There is nostalgia in it like real Coke vs store brand cola.

Certainly a +1 for point 1 :)

There are also purists who won't modify their minifigs at all

@Joubarc: I have found that people who view my collection, enjoy my minifig modifications more than the models I have built.

What is the reasoning to why one might build using solely LEGO? Is it just an affectation, or is there some deeper meaning? Is there something particular about LEGO as a building toy to which inspires this way of thinking? I am interesting in understanding both sides of the argument.

I agree that this question is highly subjective, but it reminds me of several discussions that I've heard or participated in.
Many of the purists that I've spoken with have mentioned that they've enjoyed the challenge of building something with a limited palette. The restriction to only use LEGO parts challenged their creativity and forced them to work around issues without using non-LEGO parts that would make the project "easier." As other posters have noted, they felt that using non-LEGO parts was "cheating" - a highly personal opinion.
One other factor that some purists have mentioned is that this restriction to use only LEGO parts also permits any other LEGO builder to replicate their project, if so desired. Some of these builders were scientists, and they liked the idea of being able to reproduce a project.
I've also observed a sliding scale of purism - ranging from the use of only LEGO parts but permitting the use of glue/stickers to the use of only official LEGO parts/stickers.
On the other hand, my non-purist friends just want to make cool projects and don't care what parts or techniques they might use to accomplish their goals.
Again, there's no right or wrong answer, but I found that the purists enjoyed the challenge and wanted to allow others to replicate their work, while non-purists just liked the joy of building.

IMHO: It's a matter of quality, physics & imagination. To me, non LEGO elements visualy "clank" when viewed amongst a LEGO scene. I can't stand Megablocks. The pieces are  inconsistant & quality control is poor when measured by the LEGO standards. As for what lurks beneath the surface of a LEGO model, well, I suppose it all depends on what you are making. Some models require creative solutions. Hidden frames & underlying supports certainly reduce the number of unseen pieces required in a display & give you the ability to flex your LEGO imagination by freeing those elements up so you can add them to your build.
Now my answer to the question: LEGO elements seem to flow and blend nicely. Their quality is excelent, and the overall playing experience is satisfying. Mixing in other elements into a LEGO build somehow seems to reduce the visual impact of the model. So, I say it's the outside that counts. Master Builders may use shims, but friends don't let friends use Megablocks.

Is there something particular about LEGO as a building toy to which
  inspires this way of thinking?

No - it's just the way humans are. At a very basic psychological level we make distinctions based on the most arbitrary criteria. In many activities, a 'purist' group will emerge, as will an 'extreme' one etc.
I think I have been mostly a purist, but that is just because there are so many things you can do with basic sets that I haven't needed to modify.
I am a definite purist though when it comes to the merchandise LEGO kits (like the star wars ones, or any with a piece that can have only one use - a cockpit canopy, or a strange wing element, for example) - I reckon keeping it old school is much better :-)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Bridge from just basic bricks?
I teach an after-school engineering class using LEGO bricks, one of our classes has the students build a bridge.  Each student gets a custom set of about 150 2x4 bricks, about 300 2x2 bricks, and, if I'm feeling generous, about 15 2x8 plates.  Although I've seen many fancy bridges made with technic parts, I've never seen an awesome bridge made with just basic bricks.  I'm looking for a reference bridge to show the kids, after the build their own, what is possible.  So, show me the best bridge (either a link to someone else's bridge , or a photo of your own) that can be made with just basic bricks!
Scope note: Most people don't have this custom set of bricks, so links or pictures of any bridge that uses almost no rare parts and use almost no technics would be cool.
Background:
LEGO Bridge Page: http://lego.sparre-andersen.dk//Transport/Broer/
Arch from archive

Cantilever from archive

Big:  from archive

Sort of basic arch: from flickr

From the FAQ:
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much.
If your motivation for asking the question is “I would like to participate in a discussion about __”, then you should not be asking here.

I don't think "off-topic" is the right close vote here...

I think a better question would have been: How do we make [this bridge - with picture] more robust? With a picture of the bridge in question, or something like "How would you go about about building a functional Cantilever bridge using the following components?" and then tag it [tag:technique] or similar

I disagree that this is off topic.  I think Joubarc's answer is perfect.  The question is practical - I face this problem.  And although it is open ended, it is not inherently open ended, any more than any 'what is the best'  type of question, which are often asked and answer, for example, on stack overflow.  I do like Zhaph - Ben Duguid's suggestion as being significantly more constructive and less discouraging than simply closing this.

Pubby8 asked this http://bricks.stackexchange.com/questions/273/what-is-a-good-ratio-to-buy-bricks-in I feel that either these should both be closed, or neither should be.

I think Lee DeLapp was just plain wrong. This question should not have been closed.

@ErikOlson and AscendlyJJ: At this stage (private beta), both of you should be able to vote to reopen this (I have done), or vote to close the others. Oezi's question as originally asked was even more off topic, being related specifically to programming mindstorms. Just commenting doesn't really help ;)

I've added this as a meta topic for discussion http://meta.bricks.stackexchange.com/questions/59/will-all-open-ended-questions-be-closed-i-certainly-hope-not

Ok, I never saw a reopen on stackexcange before!

@ascendlyJJ: "What's the best" questions are such a pox on SO the word "best" automatically pops up a warning when asking a question! Please don't try to justify this question with that example...

If you also want them to be aware of the solidity of their bridge, you may want to have a look at this contest.
Note that bridges made of stacked plates are much more solid than Technic ones.

To prevent the stack-of-plate loophole, most Lego bridge contest now have a weight limit.

Since you mention an engineering class, I assume you probably mean a functional bridge that can be tested for capacity.
This bridge may not withstand a great deal of weight, but it appears in a 1964 LEGO Idea Book and is created only from basic bricks available at that time. (LEGO did issue a more detailed Tower Bridge set a few years ago)


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Where can I find LEGO technic pieces?
I love the design by me software, but there are too few LEGO Technic pieces.
Do you know somes places (in Europe) where I can find LEGO Technic pieces without buying sets ?

http://bricks.stackexchange.com/questions/220/whats-the-most-cost-effective-and-efficient-way-to-buy-bricks covers all bricks, and so Technic.

Directly from LEGO:

Pick a brick

Third party:

bricklink.com

bricklink is cheaper in most cases, on both you can choose and buy only the pieces you really need.

I'll pretend I didn't read the "without bying sets" part.
Go buy some!
Seriously, this is the simplest way to acquire good packs of assorted Technic parts, and if you haven't got much experience with Technic yet, building the models is a great way to learn.
Of course, some models are better than others in terms of assortment provided , but I don't know for sure what's the best value for money at the moment. Whether you want electric or pneumatic parts will play a role, as will possible clearances in your area.
If you can find a LEGO education reseller, they also carry Technic parts packs, but BrickLink is probably going to be cheaper anyway (you can filter by country, too — buying from someone in your country is usually easier and cheaper).

some times i just need an extra worm or motor, i will not buy a set just for 1 or tow pieces

My mistake, I was under the impression you wanted to buy more parts. So yes, for spare parts, oezi's answer is better. I maintain that LEGO education could be interesting (but in Europe you'd have to find a resller first and it'd usually be too expensive), and eBay may have good surprises, but Bricklink is the way to go when you know what you're after. One last thing on motors: LEGO also sells them individually in the Power Functions section instead of the pick-a-brick one.


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Is "public transport" train compatable with Lego City track?
Among other things, set 8404 contains a train but it doesn't come with any track pieces (see set 7499). Is this train compatible with these Lego City tracks? I see where it's more of an electric trolly and if it's not track compatible, is it at least wheeled?

It uses train wheels which means it should work on Lego track.

Sources:
Bricklink set inventory
LEGO Building Instructions lookup

It is designed to handle curves that are found on CITY track. Here is the detail from middle car. There is tongue and groove that allows the middle wheels to slide left and right to enable curves. I will post a video of a powered train pushing it, if needed.

Cheer's Craig, very helpful detail :)

To a degree, Yes. The tram works well on straight pieces of track. It doesn't look like the tram was designed to be used with CITY track.
The wheel axles are fixed to one point so they cannot navigate curved pieces of track easily. A simple modification should be able to fix this.

The wheel used are smaller than regular train wheels and are usually never used in train sets; but more for smaller train-like stuff (Spider-Man metro, Indiana Jones mine cart, track buggy, track maintenance vehicles...)
So they will work on regular track, but their smaller size mean they're more likely to derail, and they have more friction around the axle than normal train wheels. Straight track is definitely OK, curves will presumably be good too, but be careful around switches.
In any case, a lot of fans use the same wheel to build their own trams, and some even manage to motorize them.


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What pieces are prone to breaking?
I've had a few pieces break over the years, which was a real bummer as I was not expecting them to.
What are some commonly used pieces that are prone to breaking? Pieces that should be handled carefully and stored separately.

This might be better as a community wiki, as there are multiple correct answers.

I didn't know Lego bricks could break! I realize there is a theoretical limit but I've never seen damage.

A single answer might be better as CW, if we are to build the list ourselves rather than find an external resource; not the question.

I had a leg peice break. I never have had this happen.

Easy one: the space helmet.

chairs break quite easily when your brother steps on them

Lego is generally quite robust, but there are potential weaknesses:
Material Problems
Some parts are prone to damage as a consequence of the material from which they are made:
Plastic

Sunlight can cause discoloration
Bricks can be damaged by extremes of temperature
Older bricks (pre ABS) are prone to warping, discoloration and may become brittle
Most plastic bricks are easily damaged by pressure (eg. from teeth) and abrasion

Stickers

Most are easily damaged by water
Wear easily
Are easily damaged when they span components

Rubber

Rubber bands tend to perish

Structural Problems
Damage can also be caused due to the shape and structure of some components:
Long Parts
Long thin parts are prone to bending or snapping under load, for example:

Long technic beams
Flags, signs etc. with long stems
Larger plates and baseboards
Swords
Propeller blades

Clips and Other Joints

Lego clips are prone to breaking under stress, for example:

Minifigure hands
Flags that clip on to flag poles
Bricks with clips on
etc.

For older types of window frame, the lugs that hold the shutters can snap off quite easily:

Ball sockets can break if you force the ball out by levering it against the socket instead of pulling it straight out.

The hinge holes on chests can be stripped out by pushing the lid open too far

Technic Parts

Wheels and gears can crack under stress
Smaller items that fit on technic (axles bushes and the smaller cogs) are easily crushed

Other Parts

It is rather easy to supply excessive force to angle brackets eg. by stepping on them or when they are at the junction long parts that can apply leverage

Electronics
Electronic items have special problems:

Battery boxes can be ruined by leaking batteries
Electrical items can be damaged by applying the wrong voltage, eg. 12v to 4.5v lamps
Most electrical items can be damaged by water
Cables break easily, and (at least in the case of the old 4.5v system) can easily be pulled from plugs
Some conductors are prone to corrosion

Recommendations
I recommend:

Sort lego before washing to remove parts that will be damaged by water
Don't play with lego on the floor where it can be stepped on
Keep bricks out of sunlight
Don't let bricks get too hot
Keeping lego away from children(!) and pets
Remove batteries when not in use

"Keeping lego away from children" - I think that's the most cruel thing I've ever heard.

@Joe: ...and not quite serious! (I've aready bought my 7-year old more lego than I've ever owned myself) At the same time, I don't let him play with my vintage / collectors items. He just isn't ready.

Not making any children is safer, IMHO

"Don't play with lego on the floor where it can be stepped on". That's more for your own safety. Walking barefoot on small lego pieces hurts. A lot.

If I wouldn't have played with LEGO when I was a kid most likely I would be an engineering PhD student in one big university of the UK. LEGO are the ones that brought me here, so Keep LEGO close to children

Minifig Hands (and skeleton arms) - if you replace/change tools often
Axles - be careful where bearing loads, long axles make easy weak points.
Gears - I've had cracked 24t gears - old style, cracked old style crown gears, and those tiny bevel gears, the old style - I've had those broken too.
Pneumatic system push fittings - I've seen sheared off.
Electrical cables - these can get caught up and kinked which will break the signal.
Lego space - whip antenna -  - these can snap in the long fragile stem.
Longer accessories - such as Swords and Spears can be bent and broken.
Technic 2M Cross Axle with Groove  have been snapped under load.
Lego-made rubber bands exposed to oxygen degrade over time.

The pieces that broke most frequently for me were the 2-by-2 square flags:

They are often used in pirate sets as cannon porthole covers (shown in red on the Black Seas Barracuda). The clips tend to break very easily.

Especially when people put them on the wrong sized pole :(

I would say the most breakable piece, in my opinion, is the Plate, Modified 1 x 1 with Clip Horizontal.

I've had quite a few of these break:

Peeron calls them Minifig Mechanical Arm (id 30377). Apparently Lego calls them Space Skeleon Arm (I'm guessing that should be Skeleton, but no idea)
They're used as door hinges in the City Passenger Plane:

Wheel 30.4 x 14 VR has the tendency to crack around the axle under high stress.

The ones that break for me are the sockets for the ball joints.  See http://www.flickr.com/photos/grandpappy/3988584161/...

Minifigure hook hands are easily broken — especially the gold-coloured hooks from the 2010 Pirates line, as the material used for gold pieces is rather fragile.

It isn't even a fair contest. In my childhood of playing with Lego Space sets, this piece (Bracket 2 x 2 - 2 x 2) broke the most.

What, in your experience, causes them to break most easily?

I think there were two reasons. When used in building it was used to attach pieces which ended up being horizontal, so if there wasn't enough support underneath you could flex it at the corner of the "L" and break it. The second reason I believe is that I had all bricks in a big bucket, I think the act of sifting through the pieces may have put stress on the piece enough to bend it and it would break. If I had compartmentalized storage that may have saved some pieces.

I too had a few of these pieces break, but not many other pieces. This is only wild speculation on my part, but it may be to do with a combination of two things: Design - Mine cracked horizontally between the studs across the hole, which is probably the weakest point due to the least amount of plastic. Sun exposure: My classic Space sets that used these pieces have quite a lot of fading and maybe the UV exposure made them brittle.

The ones that gave me the most trouble were the "new-style" BIONICLE axle connectors like this one:

It seems that the parts holding the axle ball were much thinner than on the previous versions, and they tended to crack and break from extensive use. It was possible to use some cracked ones, but some broke beyond that.

98% precent of all the broken LEGO pieces I own are colored in reddish brown. I've broken a lot of them too. Just broke one right now, in fact. They probably use a weaker type plastic on them. I seem to be the only one who's ever noticed this.

At some point of time elements in Dark Red were prone for braking a lot. Especially 1x1 tiles. It seems like this issue has been addressed by TLG.

I remember that back in the day (which would be mid eighties), I had a number of 1×1 translucent plates split on me. Right through the middle — and then I had two halves. They would typically split either when trying to connect or disconnect them to/from a regular stud. No idea if it was a bad batch or what. Haven't had that happen with more recent versions.

I see no mention of Lego propeller blades. Both when I was a child and now in my kids' LEGO collection I find it hard to get a propeller that doesn't have at least 1 blade broken off.

I've had one or two long technic pins (part 6558) break on me.

This weekend I sorted through some boxes of lego that have laid dormant under my parents' house since I moved out. They contained bricks from the 80s to late 90s. THe only broken pieces I found where these technic chain pieces, crushed at the bottom of the box, and lego traffic signs broken off at the base. I can reuse the traffic signs by sticking them into a 1x1x1 barrel piece, but the chain is ruined and I'll need to buy a whole new one.

Without about the hinge plate. All three I had in 6652 and 6678 broke at the time which was really disappointing in pre-Internet times as you had no way of replacing them.

Slope 30 1 x 1 x 2/3, better known under "Cheese Slope" name is another element that tend to crack even in the modern days no matter what color is being used.

Technic U-joints are also quite vulnerable parts in motorized applications.

1x1 plates in transparent colors (mainly red and green) from the Lego space sets in the 80's/90's seem to use a plastic that is very brittle to start with and doesn't age well.
Just pushing one of those onto a stud can be enough to break the piece in 2 or more parts.
I just rebuild all my old sets over the Christmas holiday to identify and replace missing/damaged parts and I found I needed to replace 12 of these, out of a total of 31.
I broke about half during the rebuild. The other half were already broken 20 years ago when the pieces were relatively new. I recall that 1 snapped when it was brand-new on the first time build when I bought that set around 1995.)


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How would you make a good pivot-arm suspension?
I once tried to make a 4 wheeled Lego robot using a pivot arm suspension system. The robot was motorized using 2 Mindstorm (2.0) motors (one one each side).  I can't find and original picture but it looked like this big black one:

I used a Lego Technic turntable as the single point of rotation between the two robot sides bu the robot sagged a lot and there was so much pressure on that piece that it would not rotate well.

Q: How would you build a 4 wheels rover pivot arm suspension system? Considering that it needs to be motorized thus adding the weight of two motors.
Note: The pivot arm design can be one of those two:

Edit 1: To give an idea of the size, I'm using this Technic wheels. The final model is about 20cm long and 20cm wide.

Some versions of the Technic turntable have more friction than others. If yours doesn't rotate freely, chances are that it needs some surgery. Unfortunately I'm not sure what exactly you need to trim, but I know you'll need to open if first.

@Joubarc I tried two different Lego turntables with the same results. To be sure, I'll look into the part like you're suggesting.  Still, I think that there was way to much torsion (perpendicular to the turntable plane) applied to it and this is why I'm asking around for other design ideas (before I do this with non-Lego parts).

Yes, another design might be better anyway, I was mentionning this just in case.

If you're into robotics, why not join the Robotics Proposal?

I got inspired by the idea of a vertical Slewing Bearing.  I made this “horrible”  prototype to demonstrate the principles.

One side of the assembly has a fixed wheel attached to it using multiple pins. The other side has multiple bearings.  The idea is that the vertical weight is shared between the bearings (on one side) and between the pins supporting the wheel  (on the other side).  This way, the axle supports only a part of the weight.  In the final design the axle should be much longer and use many bushes preventing the two sides from separating.

In the end I will build a system like this one.  When get to it I'll post a link to pictures.

This may sound like a naive approach, but isn't the turntable overkill in this case?
Did you try a simple Technic pin peg to connect both parts if the robot, or do you actually need some transmission to go from one half to the other?
If a Technic peg isn't robust enough, maybe an axle would do the trick. I'd suggest using one Technic Axle 8 with Stop (), on which you first slide 3 regular Technic, Brick 1 x 2 with Hole () which will be attached to one half of your model, then 5 Technic, Brick 1 x 2 with Axle hole () which will be attached to the other. Maybe the strain on the axle will be too much (I read it's prone to breaking), but it could be worth trying.
And if that's not solid enough, build a staple of 2x2 round plates around an axle, fix that to one half of the model, and build a hole on the other half to have it slide in (a square hole is fine and easy to build: just a two bricks wide, two bricks high gap and you cover the studs underneath with a tile. Use archs if you want for the higher half, but don't bother for the bottom one). Of course you have to finish the pseudo-axle with something bigger than 2x2 to lock it in place.
And if THAT's not enough, there are 4x4 round plates now with which you could do the same.

+1 you solution using round plates on a axle sounds really nice (the 1 axle- or peg-solution is so easy i can't belive pcantin hasn't thought of it himself)

This was my first option but it would have snapped under the weight of the two sides.  I've added a picture of the wheel size that I'm using.  Imagine that plus a motors and gears on each side plus the structure. The single axle design would not survive (unless it supplemented with some other support).

I was thinking along the lines of a Slewing Bearing.  I've seen designs like that used for massive Lego tower cranes.  This gives me an idea [off to the Lego boxes]...

Spread the weight using gears.
Essentially you'll have 4 segments connected to a center gearbox. Use 9 bevel gears in the gearbox, with 6 on the outside.

(Yellow=bricks, Black=rods, Grey=gears)
For strength you can have reinforcements going from the gearbox to the other side of the legs to box it in.

I'm not sure I understand your design. Would this behave like a rocker-bogie suspension? (like the MER rovers).  I don't see which gears are really connecting. Can you clarify the sketch?

@pcantin I don't know how to explain it other than the axles on one side spin the opposite direction of the other.

would you mind trying to design it on LDD and posting pictures?

Can you add like a red line indicating where the gears are supposed to mesh?


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Under what conditions are the LEGO boardgame dice unfair, and by how much?
For LEGO's board game line, they have moulded a LEGO die, with a 2x2 stud pattern on each side.

Obviously, weight distribution is going to be thrown off if you use a full studless plate on one side and four 1x1 studless plates on another because of the kerf.
Experimentally (by constructing different dice and rolling hundreds of times) or analytically (by analyzing the weight distribution of different plate configurations), how unfair can this die be assuming all studs are covered by a studless plate? What can be done to minimize the unfairness?

If you want to be torough, your assumption about all studs being covered has de be rescinded. Indeed, some of the games make heavy use of the "build your dice" feature, and add or remove tiles during the game itself. This adds a whole new dimension to the dice mechanics as event probabilities change over time, even if you ignore the unfairness introduced by the weight difference. Minimizing the unfairness can be of course by using only 2x2 tiles, but where's the fun in that?

I don't think I've played a Lego game yet that allows empty die sides? Or perhaps I forgot - some of the games are fairly unmemorable. I'm also interested in any unfairness that may manifest for a plain die covered in 2x2 as well.

I don't expect much unfairness if all sides are covered by 2x2 tiles. From what? The paint? The LEGO dice is probably much more balanced than a regular Monopoly engraved dice. As for games where sides are built during the game, a lot of them do, and I think Lava Dragon is a good example: when you roll the dice, if there's room on the upper side, you may add a 1x1 tile of your color, then you can make as many moves as there are tiles of your color on that face (or something like that).

Indeed, Lego's manufacturing genius has probably resulted in an extremely fair die - but like I said in the question, a good answer will be something empirical or analytic, and not assumed. (Lava Dragon is one I haven't played yet.)

Conditions for unfairness:

Different shaped tiles applied to each side resulting in different weight wich maked the dice "biased."

Example:
The maximum difference in weight (when all studs get covered) is one side using a 2x2 tile, and another side is using 4 1x1 tiles. the weight difference in this case is calculated based on using these measurements. To show the difference:
X X X X X X X X X X
X       . .       X
X       . .       X
X       . .       X
X . . . . . . . . X
X . . . . . . . . X
X       . .       X
X       . .       X
X       . .       X
X X X X X X X X X X

X = borders
. = border from the 1x1 tiles that are missing using a 2x2 tile
So there are ~ 28 legounits³ = 44.8 mm³ difference in material used. ABS, the material used for LEGO bricks has a density of between 1.04 and 1.12 g/cm³ so 44.8 mm³ have a maximum height of:
1.12g/cm³ / 1000mm³ * 44.8mm³ = 0.050176g

0.05 g would be way too much for a precision-dice used in a casino, but for a "toy" it's almost nothing (it's less than 1% of the die's total weight - I'd like to calculate that, but I can't find information about its weight), so I won't expect anyone to notice the LEGO-dice is "unfair".
EDIT:
Found the dice on bricklink. weight: 8.02 g, so the 0.05 g are just ~ 0.6 % of the total weight.

Actually, BrickLink will give you the weights for tiles too. A 2x2 is 0.48g and a 1x1 is 0.16g so the difference between one 2x2 and 4 1x1 is 0.16g. Which is not the highest unfairness you could have; as I said you can have empty sides, so the highest unfairness is empty side against 4 1x1 tiles, or a difference of 0.64g, or 8% of the total weight, which is bound to make a difference. Although usually when an empty side comes up you may add stuff on it so the situation is unlikely to happen.

i've chosen to compare 2x2 against 4 1x1 because that was one of the things asked ("a full studless plate on one side and four 1x1 studless plates on another"). the difference in this cas eas also much more interesting as the dice gets filled quickly and as long as there are empty sides its obvious the weight-difference is much higher.


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How strong are blocks in general - is adhesive necessary when building large structures?
I'm really intrigued by all the amazing bridge architecture and designs people come up with (for example: Lego Cable Stayed Bridge) and it got me wondering, do larger structures like that need any form of adhesive between the bricks?  Are bricks (in general) strong enough to hold larger structures on their own?

Gluing Lego should be a crime :)

@pcantin Yea, I agree in theory, but I wasnt sure if it was necessary for certain things.

I have had to use glue on MOCs when they received enough heat damage to the point where the clutch on the pieces fails to hold it together anymore.

Such structures in LEGOland parks are usually reinforced with a metallic structure hidden within the model. And they use glue. No wonder LEGO sold them away.
Some fans do use similar tricks, I've seen some make trees by embedding a wooden skewer in a trunk of 1x1 round bricks. Without that, the tree would collapse too often, and that's not even a large structure to start with. (Purists would use rigid 3mm LEGO hoses)
For a pure LEGO structure, in any case you would need to make sure not to rely on clutch power only, but I suppose you guessed as much already. As stack of 1x2 bricks won't hold, a length of interleaved 1x2 plates will be sturdier. Depending on the length, you'll need more layers, but that's about it.
I doubt adhesive would help that much — glue maybe, but let's not go there.
There`s the question "How much weight can a handle of Technic pegs and beams support?" covering the principles for structures. You can find a mechanical stress study right here.

Very interesting.  I didnt even think about some of the internal support methods of reinforcement!  Thanks for the good infos!

It's also quite common to see Technic skeletons used inside of Lego builds to hang the rest of the pieces on.  Lego itself uses this technique in their larger UCS Star Wars sets.

For building anything of normal Lego size, the bricks generally stick together nicely if you overlap your bricks during construction. If you are making something of great size, walls of 2 or 4 dots using an overlapping pattern will produce something quite strong.
Because of the shape of Legos, they are weakest when pulled from the bottom. They are designed to rely on Gravity for strength, not to work against it. So, if you move something heavy, the bottom of the model must be supported or a portion of it will likely pull loose.
And of course, if you are building something permanent, like in Legoland park, the suggestions above to glue and support the internal structure are valid. But for typical home use, it is unnecessary.


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How do I create manuals in the same style as LEGO instruction manuals?

Possible Duplicate:
Do any programs exist that allow you to build your own LEGO manuals?

I want to create my own manuals, but I want them to look and feel like actual LEGO instruction manuals. So, I probably need a style guide and / or tool that helps me to achieve this. Are these tools and style guides available?

I'm afraid I'm not clear about my question. :) I'm not asking for actual building tools, but for style guides. I'll update my question.

Ah, would you be talking about getting the right type of paper and printing and assembling it? If so, then this is certainly not a duplicate. :)

That's what I meant. Sorry about the confusion. :)

This was clarified not to be a duplicate after several people voted; unfortunately there is no way to rescind close votes. (On the other hand, an answer was accepted that doesn't jive with the clarification. So I have no idea, really.)

I thought there was a way to vote to reopen a question. Is there? Cause I'm not seeing one.

The online consensus on this question seems to be using LDraw, and progressively create the model while saving the steps (like this tutorial explains).
However, I remember an other way, but I can't put .. oh wait, it was using MLCad.

LPub is a program designed specifically to produce step-by-step construction documentation from LDraw files. I haven't tried it myself (it's Windows-only) but I believe most of the fan-created instructions out there are made with it.
Edit: As Retracile notes in his answer to a similar question there is a newer version, LPub 4, which also supports Mac.


text:
How can I build a functional gearbox?
I'm looking for a fully functional (manual) transmission / gearbox for my Technics motorized vehicle. How can I build this?

there are some lego-models that have a working gearbox built-in like the super street sensation (8448). just take a loot at the building instruction* to see how it works.
*page 18, 26, 72-81

Funny that you are asking because I just rebuilt my old 4x4 OffRoader (8466) with my son. it's a 4 wheels drive, V8 with a functional 5 speed gearbox (including reverse).

and in the truck (with the gearbox cover):

Looking at it in action is really good to understand the basics of a car's transmission.

I made a compact 6-speed, which you can find CAD and .pdf instructions in this brickshelf folder. (Maybe one was reverse, I don't quite remember...)
Please bear in mind that it wasn't intended to be motorized and might not perform well under load. However it should give you an understanding on how it can be done.
If you do not have those special gearbox transmission parts, you can do it by sliding a cross-axle with gears on, in one position it will be connected to one gear, in another position it will be connected to another gear. See this design by Sariel for clarification.