Answers.Body: <p>There is another piece with an odd LDU dimension: the 1x1 bracket is 3 LDU thick. Paired with an Erling brick, which has a 4 LDU offset built in, it's a very compact way to create a 1-LDU offset, <a href="http://www.flickr.com/photos/pmiaki/7451841124/" rel="noreferrer">like psiaki has done here</a>:</p>
  
  <p><img src="https://i.sstatic.net/y5RWV.jpg" alt="1 LDU steps by Psiaki"></p>
  
  <p>Then it's just a matter of translating the offset into a gap between bricks using standard bracket pieces <a href="http://www.flickr.com/photos/62bricks/8569712094/in/photostream/" rel="noreferrer">like I have done here</a>:</p>
  
  <p><img src="https://i.sstatic.net/Evysl.jpg" alt="1 LDU gap">
  <img src="https://i.sstatic.net/x8ESc.jpg" alt="enter image description here"></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-03-18T20:32:25.163Z
Answers.Text: nice one, I didn't know about the 3 ldu bracket
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-03-18T18:44:46.033Z
Answers.LastActivityDate: 2013-03-18T18:44:46.033Z
Answers.UserDisplayName: 62Bricks
Answers.Body: <p><a href="https://bricks.stackexchange.com/questions/691/what-are-ldus-and-how-do-they-relate-to-lego-bricks">LDUs</a> are synthetic units for LDraw, a lego design software. </p>
  
  <p>(I am personally convinced that the correct answer to your question is that there is no way to create a 1 LDU gap and that we are very fortunate to have the <a href="https://bricks.stackexchange.com/questions/39/what-is-an-erling-brick">Erling</a> brick to create a 2LDU gap.) </p>
  
  <p>If you look at the 2 links provided, you'll see that both the Erling and the standard lego brick dimensions only have even values. There is no way to end up with an odd number in these conditions.</p>
  
  <p>If there is a solution, it must involve a brick that has an odd dimension in some direction. </p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T08:19:20.550Z
Answers.Text: Your last statement is right on the spot, and there is one such element. (Also, note that for a 2 ldu gap, the erling brick alone isn't enough as it only has dimensions that are multiples of four. That's why you need a half-brick (10 ldu) offset too, which is what the jumpers are for in my picture)
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-30T07:30:35.130Z
Answers.Text: Don't thank me, it's all automatic. You got half of the bounty award because your answer was the most upvoted since the bounty started. Well, you were halfway there, so it makes sense :-)
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T08:12:47.353Z
Answers.LastActivityDate: 2011-11-28T08:12:47.353Z
Answers.LastEditDate: 2017-04-13T12:47:56.213Z
Answers.UserDisplayName: jfyelle
Answers.Body: <p>Using <a href="https://www.bricklink.com/v2/catalog/catalogitem.page?P=42446#T=A" rel="nofollow noreferrer">42446</a> bracket with a regular <a href="https://www.bricklink.com/v2/catalog/catalogitem.page?P=36841#T=A" rel="nofollow noreferrer">36841</a> bracket you can create pretty small builds.</p>
  <p><a href="https://i.sstatic.net/ePol2.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ePol2.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.sstatic.net/iXHjV.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/iXHjV.png" alt="enter image description here" /></a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-05-13T16:44:35.773Z
Answers.LastActivityDate: 2021-05-13T16:44:35.773Z
Answers.UserDisplayName: Geri Borbás
Answers.Body: <p>This is a very very silly solution, but it <em>should</em> be possible with gears.</p>
  
  <p>Get the ratio correct and you'll be at 1/4 rotation per 1ldu. Then slide in one of these:
  <img src="https://i.sstatic.net/LzcW5.gif" alt="">, lock the axel and you're capable of any ldu spacing.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-25T05:04:04.850Z
Answers.Text: Sounds ingenious, but I'm not entirely convinced. It's nearly like a continuous solution (I'm looking for a solution with pure stud connections), and the calculations must be horrible.
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-24T22:27:27.743Z
Answers.LastActivityDate: 2011-11-24T22:27:27.743Z
Answers.UserDisplayName: Pubby
Answers.Body: <p>(Note: my HDD crashed recently and until I get that fixed I can't really make LDraw images. I did create one for this beforehand, but it's on the same HDD.)</p>
  
  <p>As jfyelle <a href="https://bricks.stackexchange.com/a/736">said</a> the solution consists of using one LEGO element which has an odd ldu dimension somewhere. There is such an element, which isn't even new or particularly rare, that is, the <a href="http://www.peeron.com/inv/parts/3185" rel="nofollow noreferrer">Fence 1 x 4 x 2</a>:</p>
  
  <p><a href="http://media.peeron.com/ldraw/images/7/3185.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/c7yyU.png" alt="Fence 1 x 4 x 2"></a></p>
  
  <p>The centre part has a thickness of 6 ldu, which means that there are 7 ldu on each side. So if you add a 2x4 plate in it, the thickness of the plate (8 ldu) means that it will stick out by exactly one ldu. If your fence is one red brick, just put a 1x4 brick and a 1x4 brick with for knobs on the other to connect to the plate. Your two red bricks should then be 1 ldu apart.</p>
  
  <p>I did learn that trick from Didier Enjary in his excellent <a href="http://news.lugnet.com/announce/?n=3429" rel="nofollow noreferrer">Advanced Building
  Techniques Guide</a> which is well worth reading. That document contains a whole chapter on offsetting, but curiously the 1 ldu offset isn't listed explicitly; rather, the fence element and its 7 ldu offset is mentioned casually in the SNOT section. </p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:29:20.977Z
Answers.Text: Full credits and my thanks go to Didier Enjary. I tried to have him come and answer himself, but he declined. Note that he also thinks the practical usefulness of the this is very limited.
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:37:47.980Z
Answers.Text: That was a hard question :)
Answers.UserDisplayName: jfyelle
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:39:50.147Z
Answers.Text: It's even harder to judge the difficulty of a question when you already know the answer.
Answers.UserDisplayName: Joubarc
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:47:29.160Z
Answers.Text: Well, I was impressed I could came up with the principle. I'm away on a business trip however and couldn't really afford to browse the bricks for a solution.  I'm sure I would have dismissed the puny fence.  By the way, for your crash, get yourself a standalone solid state hard drive and use syncback to backup your stuff.
Answers.UserDisplayName: jfyelle
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:50:27.590Z
Answers.Text: @Joubarc: That's truly brilliant! Many thanks for the posing this entertaining little puzzle. It's been bothering me for *days*. Now I'm *kicking myself*. The first time I ever came across SNOT it used these very same fences!
Answers.UserDisplayName: Kramii
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-28T13:27:34.973Z
Answers.LastActivityDate: 2017-04-18T22:17:58.413Z
Answers.LastEditDate: 2017-04-18T22:17:58.413Z
Answers.UserDisplayName: Joubarc
Body: <p>LDraw units are defined so that a simple 1x1 brick has a side of 20 ldu and a height of 24 ldu.</p>
  
  <p>Using simple building techniques, it's easy to create 2 ldu offset, as illustrated in this picture, where the gap between the two red bricks is 2 ldu wide:</p>
  
  <p><img src="https://i.sstatic.net/NNijw.png" alt="2 ldu offset"></p>
  
  <p>Of course, it's also possible to build any kind of offset, including 1 ldu, using continuous techniques such as parts gliding on axles, as illustrated in this picture:</p>
  
  <p><img src="https://i.sstatic.net/MDYKt.png" alt="1 ldu offset, continuous"></p>
  
  <p>But is it possible to build an exact 1 ldu gap without this kind of cheap trick?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-23T22:32:20.487Z
Comments.Text: I don't have an answer, but I do know this: the dimensions of basic bricks are multiples of 2 ldu. That means that any rectangular arrangement of bricks can't possibly have a gap of 1 (or any other odd number) ldu. Any solution to this problem will, therefore, involve bricks with odd dimensions or bricks placed at an angle (i.e. some kind of SNIR technique).
Comments.UserDisplayName: Kramii
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-24T05:37:18.700Z
Comments.Text: Good thinking, but SNIR is not what I have in mind here, no angles other than 90° are required.
Comments.UserDisplayName: Joubarc
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-24T10:02:57.043Z
Comments.Text: Perhaps we could use the fact that bricks are not *exactly* 20 ldu wide: they are actually 0.25 ldu short at each end (which means that an ordinary lego wall has gaps of 0.5 ldu between the bricks)? Or that the studs on system bricks are approximately 0.25 ldu lower thatn the holes on technic bricks?
Comments.UserDisplayName: Kramii
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-24T10:14:51.407Z
Comments.Text: The fact that bricks are slightly shorter is not in my opinion a valid solution, as the distance between studs is what will ultimately be of importance. However, your idea using Technic bricks could actually work. I didn't think of that, but I have to admit it would be quite clever, not to mention you can go to 0.25 ldu offsets which is even better. See if you can work it out as an answer by having two red 2x4 bricks with a 1 ldu gap in between!
Comments.UserDisplayName: Joubarc
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-28T07:39:55.730Z
Comments.Text: Yay, one more "don't-care-to-explain" downvote. Gotto love these.
Comments.UserDisplayName: Joubarc
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-28T08:54:42.147Z
Comments.Text: I can only guess someone felt that there wasn't much practical use for the 1LDU gap? While I can't see the use, I can appreciate the technical challenge of achieving it.
Comments.UserDisplayName: Zhaph - Ben Duguid
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-28T13:03:16.980Z
Comments.Text: Practical usefulness is debatable indeed. Very slow-sloped stairs, maybe? Even in the rare cases where it would be useful, continuous techniques are probably easier. So yeah, it's more for the challenge.
Comments.UserDisplayName: Joubarc
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2011-11-28T13:53:07.210Z
Comments.Text: From my experiments, I found that a 1 ldu offset is perfect for holding a piece of thick paper. So it does have its uses.
Comments.UserDisplayName: Kramii
Tags: <building><size><ldraw>
Title: How to make a 1 ldu offset?
UserDisplayName: Joubarc
ThreadText: # How to make a 1 ldu offset?
  
  (Asked by: username_0 on 2011-11-19)
  
  LDraw units are defined so that a simple 1x1 brick has a side of 20 ldu and a height of 24 ldu.
  
  Using simple building techniques, it's easy to create 2 ldu offset, as illustrated in this picture, where the gap between the two red bricks is 2 ldu wide:
  
  ![2 ldu offset](https://i.sstatic.net/NNijw.png)
  
  Of course, it's also possible to build any kind of offset, including 1 ldu, using continuous techniques such as parts gliding on axles, as illustrated in this picture:
  
  ![1 ldu offset, continuous](https://i.sstatic.net/MDYKt.png)
  
  But is it possible to build an exact 1 ldu gap without this kind of cheap trick?
  
  **Tags:** building, size, ldraw
  
  > **Comments:**
  > **username_1**: I don't have an answer, but I do know this: the dimensions of basic bricks are multiples of 2 ldu. That means that any rectangular arrangement of bricks can't possibly have a gap of 1 (or any other odd number) ldu. Any solution to this problem will, therefore, involve bricks with odd dimensions or bricks placed at an angle (i.e. some kind of SNIR technique).  
  > **username_0**: Good thinking, but SNIR is not what I have in mind here, no angles other than 90° are required.  
  > **username_1**: Perhaps we could use the fact that bricks are not *exactly* 20 ldu wide: they are actually 0.25 ldu short at each end (which means that an ordinary lego wall has gaps of 0.5 ldu between the bricks)? Or that the studs on system bricks are approximately 0.25 ldu lower thatn the holes on technic bricks?  
  > **username_0**: The fact that bricks are slightly shorter is not in my opinion a valid solution, as the distance between studs is what will ultimately be of importance. However, your idea using Technic bricks could actually work. I didn't think of that, but I have to admit it would be quite clever, not to mention you can go to 0.25 ldu offsets which is even better. See if you can work it out as an answer by having two red 2x4 bricks with a 1 ldu gap in between!  
  > **username_0**: Yay, one more "don't-care-to-explain" downvote. Gotto love these.  
  > **username_2**: I can only guess someone felt that there wasn't much practical use for the 1LDU gap? While I can't see the use, I can appreciate the technical challenge of achieving it.  
  > **username_0**: Practical usefulness is debatable indeed. Very slow-sloped stairs, maybe? Even in the rare cases where it would be useful, continuous techniques are probably easier. So yeah, it's more for the challenge.  
  > **username_1**: From my experiments, I found that a 1 ldu offset is perfect for holding a piece of thick paper. So it does have its uses.  
  
  ---
  
  ## 5 answers
  
  ### Answer by username_0 on 2011-11-28. Score: 14 | Accepted answer
  
  (Note: my HDD crashed recently and until I get that fixed I can't really make LDraw images. I did create one for this beforehand, but it's on the same HDD.)
  
  As username_4 [said](https://bricks.stackexchange.com/a/736) the solution consists of using one LEGO element which has an odd ldu dimension somewhere. There is such an element, which isn't even new or particularly rare, that is, the [Fence 1 x 4 x 2](http://www.peeron.com/inv/parts/3185):
  
  [![Fence 1 x 4 x 2](https://i.sstatic.net/c7yyU.png)](http://media.peeron.com/ldraw/images/7/3185.png)
  
  The centre part has a thickness of 6 ldu, which means that there are 7 ldu on each side. So if you add a 2x4 plate in it, the thickness of the plate (8 ldu) means that it will stick out by exactly one ldu. If your fence is one red brick, just put a 1x4 brick and a 1x4 brick with for knobs on the other to connect to the plate. Your two red bricks should then be 1 ldu apart.
  
  I did learn that trick from Didier Enjary in his excellent [Advanced Building
  Techniques Guide](http://news.lugnet.com/announce/?n=3429) which is well worth reading. That document contains a whole chapter on offsetting, but curiously the 1 ldu offset isn't listed explicitly; rather, the fence element and its 7 ldu offset is mentioned casually in the SNOT section.
  
  > **Comments:**
  > **username_0**: Full credits and my thanks go to Didier Enjary. I tried to have him come and answer himself, but he declined. Note that he also thinks the practical usefulness of the this is very limited.  
  > **username_4**: That was a hard question :)  
  > **username_0**: It's even harder to judge the difficulty of a question when you already know the answer.  
  > **username_4**: Well, I was impressed I could came up with the principle. I'm away on a business trip however and couldn't really afford to browse the bricks for a solution.  I'm sure I would have dismissed the puny fence.  By the way, for your crash, get yourself a standalone solid state hard drive and use syncback to backup your stuff.  
  > **username_1**: @username_0: That's truly brilliant! Many thanks for the posing this entertaining little puzzle. It's been bothering me for *days*. Now I'm *kicking myself*. The first time I ever came across SNOT it used these very same fences!  
  
  ---
  
  ### Answer by username_3 on 2013-03-18. Score: 10
  
  There is another piece with an odd LDU dimension: the 1x1 bracket is 3 LDU thick. Paired with an Erling brick, which has a 4 LDU offset built in, it's a very compact way to create a 1-LDU offset, [like psiaki has done here](http://www.flickr.com/photos/pmiaki/7451841124/):
  
  ![1 LDU steps by Psiaki](https://i.sstatic.net/y5RWV.jpg)
  
  Then it's just a matter of translating the offset into a gap between bricks using standard bracket pieces [like I have done here](http://www.flickr.com/photos/username_3/8569712094/in/photostream/):
  
  ![1 LDU gap](https://i.sstatic.net/Evysl.jpg)
  ![enter image description here](https://i.sstatic.net/x8ESc.jpg)
  
  > **Comments:**
  > **username_0**: nice one, I didn't know about the 3 ldu bracket  
  
  ---
  
  ### Answer by username_4 on 2011-11-28. Score: 3
  
  [LDUs](https://bricks.stackexchange.com/questions/691/what-are-ldus-and-how-do-they-relate-to-lego-bricks) are synthetic units for LDraw, a lego design software.
  
  (I am personally convinced that the correct answer to your question is that there is no way to create a 1 LDU gap and that we are very fortunate to have the [Erling](https://bricks.stackexchange.com/questions/39/what-is-an-erling-brick) brick to create a 2LDU gap.)
  
  If you look at the 2 links provided, you'll see that both the Erling and the standard lego brick dimensions only have even values. There is no way to end up with an odd number in these conditions.
  
  If there is a solution, it must involve a brick that has an odd dimension in some direction.
  
  > **Comments:**
  > **username_0**: Your last statement is right on the spot, and there is one such element. (Also, note that for a 2 ldu gap, the erling brick alone isn't enough as it only has dimensions that are multiples of four. That's why you need a half-brick (10 ldu) offset too, which is what the jumpers are for in my picture)  
  > **username_0**: Don't thank me, it's all automatic. You got half of the bounty award because your answer was the most upvoted since the bounty started. Well, you were halfway there, so it makes sense :-)  
  
  ---
  
  ### Answer by username_5 on 2021-05-13. Score: 2
  
  Using [42446](https://www.bricklink.com/v2/catalog/catalogitem.page?P=42446#T=A) bracket with a regular [36841](https://www.bricklink.com/v2/catalog/catalogitem.page?P=36841#T=A) bracket you can create pretty small builds.
  
  [![enter image description here](https://i.sstatic.net/ePol2.png)](https://i.sstatic.net/ePol2.png)
  
  [![enter image description here](https://i.sstatic.net/iXHjV.png)](https://i.sstatic.net/iXHjV.png)
  
  
  ---
  
  ### Answer by username_6 on 2011-11-24. Score: 1
  
  This is a very very silly solution, but it *should* be possible with gears.
  
  Get the ratio correct and you'll be at 1/4 rotation per 1ldu. Then slide in one of these:
  ![](https://i.sstatic.net/LzcW5.gif), lock the axel and you're capable of any ldu spacing.
  
  > **Comments:**
  > **username_0**: Sounds ingenious, but I'm not entirely convinced. It's nearly like a continuous solution (I'm looking for a solution with pure stud connections), and the calculations must be horrible.  
  
  ---
  
  