Answers.Body: <p>LDD uses exact numbers, where as in real life ABS and polycarbonate have some give or flexibility that a computer program can't factor in. There are many documents about LEGO part stress that explain what a "legal" vs "illegal" build is. Any illegal build will not work in LDD. I break the rules all the time too, but LDD is looking at it from a pure math sense, which you can't cheat. Try and create a curved wall made of stressed 1x2 in LDD. You can do it in real life, but not in the program.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-04-30T19:53:55.353Z
Answers.LastActivityDate: 2013-04-30T19:53:55.353Z
Answers.UserDisplayName: LEGO Train Nut
Answers.Body: <p>Try de-attaching the black piece and then attach it to the 2x2 and plate and attach all the pieces at the same time<a href="https://i.sstatic.net/JF68J.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/JF68J.png" alt="enter image description here"></a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-09-12T22:47:14.900Z
Answers.LastActivityDate: 2018-09-12T22:47:14.900Z
Answers.UserDisplayName: wow
Answers.Body: <p>Interesting... I just tried this myself (with real bricks) and the two parts definitely snap together nicely. No stress or anything. I'm wondering if the issue is the 1x2 plate. Maybe LDD can't deal with a hinged part having to snap into two places at once. What about if you remove the bottom 1x2 yellow plate? Would it snap in then? In that case perhaps first attach the 1x2 to the healight bricks, then attach the hinge-plate to the hinge, then rotate it towards the plate and see if it would snap on the 1x2 plate.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-04-28T18:43:38.380Z
Answers.LastActivityDate: 2013-04-28T18:43:38.380Z
Answers.UserDisplayName: TheBrickBlogger
Answers.Body: <p>The issue here is that the hole in a Technic brick isn't at exactly the same height as the stud on the side of a System brick. Here's a slide from a <a href="http://cache.lego.com/downloads/brickfest2006/brickstress.ppt" rel="noreferrer">great presentation</a> which explains the details:</p>
  
  <p><img src="https://i.sstatic.net/jAGiZ.png" alt="enter image description here"></p>
  
  <p>This difference is barely noticable when building, especially in your scenario because the hinge adds some additional play, but I believe that LDD won't allow these to connect because they are actually off by .12mm.</p>
  
  <p>I tried to take a few pictures to demonstrate what I mean, but they didn't turn out very well. Here's a System brick (tan) connected to a Technic brick (blue). You can just barely see the .12mm difference at the top:</p>
  
  <p><img src="https://i.sstatic.net/97Bwj.jpg" alt="enter image description here"></p>
  
  <p>The difference becomes more obvious when more bricks are added so that the error is allowed to compound:</p>
  
  <p><img src="https://i.sstatic.net/4FelC.jpg" alt="enter image description here"></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-04-29T05:04:48.820Z
Answers.Text: Seems legit (seeing the headlight brick example in the presentation slides). Just one question: is .12mm equal to 3/10LDU? That seems odd (I'm still a beginner in technical LEGO stuff)
Answers.UserDisplayName: Alvin Wong
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-04-29T13:36:16.207Z
Answers.Text: You are correct that .12mm is the same as .3 LDU, and this does seem like a strange offset. My guess is that this decision was made in order to create the absolute minimum difference between these parts. I'm guessing that most children who build with these parts have never noticed this minor inconsistency.
Answers.UserDisplayName: jncraton
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-05-02T18:04:17.200Z
Answers.Text: Great answer. I never knew about that offset. Thanks!
Answers.UserDisplayName: Peter Cassetta
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-04-28T22:10:25.647Z
Answers.LastActivityDate: 2016-12-29T16:14:17.427Z
Answers.LastEditDate: 2016-12-29T16:14:17.427Z
Answers.UserDisplayName: jncraton
Body: <p>I've built an SD card box a few years ago. Now I am trying to reproduce it in Lego Digital Designer.</p>
  
  <p><img src="https://i.sstatic.net/WgfjP.png" alt="Opened"></p>
  
  <p><img src="https://i.sstatic.net/iCUwX.jpg" alt="Closed"></p>
  
  <p>However when I tried to reproduce the closed version, LDD refuses to snap it in place.</p>
  
  <p><img src="https://i.sstatic.net/Bsu9V.png" alt="A"></p>
  
  <p><img src="https://i.sstatic.net/nYp9I.png" alt="B"></p>
  
  <p>In real-life, my box just snap very nicely. Why am I not allowed to do that in LDD?</p>
  
  <p><a href="https://dl.dropboxusercontent.com/u/39080136/SD%20Card%20Holder.lxf" rel="noreferrer">Here is the WIP <code>.lxf</code> file</a></p>
  
Tags: <ldd>
Title: Why can't I reproduce this SD card box in LDD?
UserDisplayName: Alvin Wong
ThreadText: # Why can't I reproduce this SD card box in LDD?
  
  (Asked by: username_0 on 2013-04-28)
  
  I've built an SD card box a few years ago. Now I am trying to reproduce it in username_1 Digital Designer.
  
  ![Opened](https://i.sstatic.net/WgfjP.png)
  
  ![Closed](https://i.sstatic.net/iCUwX.jpg)
  
  However when I tried to reproduce the closed version, LDD refuses to snap it in place.
  
  ![A](https://i.sstatic.net/Bsu9V.png)
  
  ![B](https://i.sstatic.net/nYp9I.png)
  
  In real-life, my box just snap very nicely. Why am I not allowed to do that in LDD?
  
  [Here is the WIP `.lxf` file](https://dl.dropboxusercontent.com/u/39080136/SD%20Card%20Holder.lxf)
  
  **Tags:** ldd
  
  
  ---
  
  ## 4 answers
  
  ### Answer by username_4 on 2013-04-28. Score: 29 | Accepted answer
  
  The issue here is that the hole in a Technic brick isn't at exactly the same height as the stud on the side of a System brick. Here's a slide from a [great presentation](http://cache.username_1.com/downloads/brickfest2006/brickstress.ppt) which explains the details:
  
  ![enter image description here](https://i.sstatic.net/jAGiZ.png)
  
  This difference is barely noticable when building, especially in your scenario because the hinge adds some additional play, but I believe that LDD won't allow these to connect because they are actually off by .12mm.
  
  I tried to take a few pictures to demonstrate what I mean, but they didn't turn out very well. Here's a System brick (tan) connected to a Technic brick (blue). You can just barely see the .12mm difference at the top:
  
  ![enter image description here](https://i.sstatic.net/97Bwj.jpg)
  
  The difference becomes more obvious when more bricks are added so that the error is allowed to compound:
  
  ![enter image description here](https://i.sstatic.net/4FelC.jpg)
  
  > **Comments:**
  > **username_0**: Seems legit (seeing the headlight brick example in the presentation slides). Just one question: is .12mm equal to 3/10LDU? That seems odd (I'm still a beginner in technical username_1 stuff)  
  > **username_4**: You are correct that .12mm is the same as .3 LDU, and this does seem like a strange offset. My guess is that this decision was made in order to create the absolute minimum difference between these parts. I'm guessing that most children who build with these parts have never noticed this minor inconsistency.  
  > **username_5**: Great answer. I never knew about that offset. Thanks!  
  
  ---
  
  ### Answer by username_1 on 2013-04-30. Score: 5
  
  LDD uses exact numbers, where as in real life ABS and polycarbonate have some give or flexibility that a computer program can't factor in. There are many documents about username_1 part stress that explain what a "legal" vs "illegal" build is. Any illegal build will not work in LDD. I break the rules all the time too, but LDD is looking at it from a pure math sense, which you can't cheat. Try and create a curved wall made of stressed 1x2 in LDD. You can do it in real life, but not in the program.
  
  
  ---
  
  ### Answer by username_2 on 2018-09-12. Score: 4
  
  Try de-attaching the black piece and then attach it to the 2x2 and plate and attach all the pieces at the same time[![enter image description here](https://i.sstatic.net/JF68J.png)](https://i.sstatic.net/JF68J.png)
  
  
  ---
  
  ### Answer by username_3 on 2013-04-28. Score: 2
  
  Interesting... I just tried this myself (with real bricks) and the two parts definitely snap together nicely. No stress or anything. I'm wondering if the issue is the 1x2 plate. Maybe LDD can't deal with a hinged part having to snap into two places at once. What about if you remove the bottom 1x2 yellow plate? Would it snap in then? In that case perhaps first attach the 1x2 to the healight bricks, then attach the hinge-plate to the hinge, then rotate it towards the plate and see if it would snap on the 1x2 plate.
  
  
  ---
  
  