Is this connection actually possible?

[NathanR]

Hi, hope this is the right place to ask this question.  I'm trying to build a small cone-shaped structure that changes diameter from 5 studs down to 2 studs with a height of only 6 plates.  Stacking 6942 "lamp shade" on top of 15395 "dome 2x2 inverted with one stud" looks like it should fit, but LDD refuses to allow this connection.  I even tried adding 1x1 plates as a scaffold.  An exploded view of the assembly is this:

I don't own either of these parts, so could someone tell me - is this really an impossible connection, or can it be done in real life?

[badgerboy]

Following your diagram with the 1x1 plates works! It needs the plates because the diameter of the intended interfacing edges of the lampshade and dome do not fit together, there is a gap. Hope that helps!

*edit*

Fwiw, I tried the parts in the real world, not an alternate digital platform.

Edited May 30, 2017 by badgerboy

[NathanR]

That's brilliant!  Surprises me that the 1x1 plates are needed though, it looks like it should just fit in like when you put a 2x2 dome on top of the inverted one.

Thanks a lot for checking this!!

[Slegengr]

I have never tried this connection with the large dish "lampshade" and I do not remember what the lower profile on that dish looks like, but I have combined the 2x2 dome with a 2x2 cone with a snugly meshing interface.  The dome also fits snugly with a 2x2 regular brick.

[anothergol]

I've done that in several MOCs, it works fine, it's just the LDD that has a collision problem there (even with a bar I had the same problem in the LDD).

 

[Superkalle]

For what it's worth, I've reported the collision error on 6942 to the LDD Team. However, I don't know if/when it will be fixed.

[NathanR]

On 01/06/2017 at 6:51 PM, anothergol said:

I've done that in several MOCs, it works fine,

Wow, awesome MOC!  I'm using these bits in a small model of the ALICE detector (a particle physics experiment on the Large Hadron Collider at CERN:

The cone elements are to represent the muon absorber, the bit sticking out to the right of the TPC:

It's hell building at this scale, but I want it sized at 1 stud = 1.5m so I can put the nanofigures/trophy statues next to it.  I'm a terrible glutton for punishment...

[NathanR]

Sorry to necro post my own thread, but I have another connection question - oddly enough on the same MOC (yes, I am that slow a designer....)

If you place a bar/clip hinge at 90 degrees, it looks like everything stays "in system" and LDD allows you to connect the orange 1x4 plate to a 99206 2x2x2/3 snot plate.  However, it turns out that the the light grey 1x2 hinge part is actually a fraction too high up, and set a fraction too far back. It's a paper-thin shift, but you can see it below when you look at the dark red 1x4 plate, m which is connected to 99206 and the others are added in after.

LDD says this is ok, and it seems to work in real life.  But is this really a legitimate connection? Would I risk cracking the hinges over time?

LXF file of the bricks: https://bricksafe.com/files/NathanR/techniques/90-degree-bar/90 dgree bar.lxf

 

[Toastie]

3 hours ago, NathanR said:

LDD says this is ok, and it seems to work in real life.  But is this really a legitimate connection? Would I risk cracking the hinges over time?

I have never used LDD - I am having serious issues with all LEGO building tools not letting me get a brick where I want it - where it actually IS in my LEGO model.

You know what? When it works in real life, I would not care the slightest bit whether or not a program tells you is it not OK. There were days when LEGO was around for decades, but programs apparently looking at illegal/legitimate connections weren't even invented. In those days, models were models you created. And that was perfectly fine. When LEGO models fall apart due to some paper thin gaps: Use pressure. ABS plastic is designed to do exactly that: Connect even better! No program or machine knows about that.

Real life is what really counts. And this is why I am using MLCad/LDraw: Just put the pieces where you want.

The hinges will never crack over time due to paper thin gaps. What will happen is that they stretch a tiny bit to adjust to your imagination. This is not esoteric wording - it is from a purely "chemistry of ABS" point of view.

Just let your ideas roll and see whether or not the bricks like it. They'll for sure let you know.

BTW: Your models and ideas are awesome!!!  

All the best,
Thorsten    

[GregoryBrick]

On 2017-10-07 at 10:51 AM, NathanR said:

LDD says this is ok, and it seems to work in real life.  But is this really a legitimate connection? Would I risk cracking the hinges over time?

I checked the math, it's in System. LDD can permit connections which 'go against' the geometry and proportions of the bricks in some cases, if I can put it that way, and I suspect it can display connections which would be aligned in real life but do not appear so in LDD, as in your example (I couldn't replicate the gap you show, but I had outlines on bricks turned off).

[SylvainLS]

I tried with lock hinges (they have the same dimensions/rules than clips but haven’t the horizontal freedom clips have) and ended up with the same paper-thin gap.

It’s just a tiny precision error in LDD.

After converting to LDR, it’s a 0.2 LDU / 0.08 mm error in both depth and height (the plate with clip is 0.2 LDU higher and 0.2 LDU more to the back (to the right in your pic)).

Actually, the center of the bar/clip is 0.2 LDU higher than it should be to be exactly in System (as it is in LDraw). It’s true for the plates with clip(s) 6019, 61252, 63868, 60470, and 11476, the plates with handle/bar 26047, 60478, and 18649, but NOT the tiles with clip 2555, 12825, and 15712, nor the plate with clip on top 92280. (I haven’t yet measured the error with lock hinges.)

Interestinigly, that’s exactly the same error LDD has with holes in technic bricks: the stud of a half pin in a technic hole should be 0.12 mm / 0.3 LDU higher than a side stud, it’s 0.08 mm / 0.2 LDU higher than that (0.20 mm / 0.5 LDU higher than the side stud).

 Thank you very much! I’ll now have to check and correct a lot of LDD to LDraw transformations for which I may have used the wrong clips as references 

[Scrubs]

Be careful with LDraw dimensions. They are not accurate to real parts due to LDU. LDD is way more correct even if some parts are a bit off. Both systems are not 100% compatible.

Edited October 10, 2017 by Scrubs

[SylvainLS]

Yes, LDraw parts have errors (the biggest one being technic holes being at the same height as side studs), but, here, we are talking about being “in System” or simply consistent. See the image below (LDD): the bars should be at the same height, they are not.

[Scrubs]

15712 in LDD is way off. Centre of hook is about 0.25mm lower than where it shall be.

[SylvainLS]

Reread what I wrote above about measures and being in System. 15712 and all other variants fo tile with clip are in System in both LDD and LDraw. That means you can do that:

(Blue brick is a 4070.)

If we couldn’t do that, the clips would be out of System. And that’s exactly NathanR’s question: Are clips in System?

Are you saying they aren’t?

Edited October 10, 2017 by SylvainLS