Lego Titanic MOC - Can't create instructions

[Mirco Hussmann]

Hello everyone,

 

while I was reading in this forum for a pretty long while now, I now signed in to ask for your help.

 

I recently designed a Lego Titanic in a pretty large scale (it is about 2.50 metres long), so loading and everything else in LDD takes a long while of course.

But no matter how long i wait, I can't seem to make my computer spit out the instructions, although I think it's not that bad of a machine (i5 4690k @ 4Ghz, 8 Gigs of RAM).

 

Could anyone give me tips what the reason could be? I also thought about splitting it in parts, but as it is that large that you can barely move big areas of it without the software freezing, I disapproved of that idea.

Sadly I don't know how to upload the .lxf here because it is too big (230KB).

 

Thanks in advance,

Mirco

[SylvainLS]

I’d suggest you try with Blueprint. LDD can’t even create workable instructions for a 100 parts model.

[NathanR]

Yeah...Lego Digital Designer is great for building models but useless for creating instructions.

The way I think it works is that it looks at every brick, and how it might connect to any other brick, to see what a good order is for placing the pieces.  The problem is that if you have say 10 bricks, then the first brick placed can be any of 10, the 2nd could be any of the remaining 9, and so on. So a 10 piece model has 10 factorial = 10! = 3628800 possible ways of placing the bricks.  A 100 piece model has 100! combinations = 9.3e157, or 9 followed by 157 zeros.  

Now LDD applies various rules to reduce the number of combinations (build from ground upwards, next brick must be close to the last one, not 2.5m away), but it's still a lot of combinations to check.  It can still end up failing, and also the output instructions only add 4 bricks per step.

Generating instructions can be a mammoth undertaking, but I would suggest rebuilding your model using LDraw (there are multiple editors available).  You can actually export your model from LDD to LDraw format (File->Export Model ->LDR) and then work with that, but a few bricks may be missing or out of place.  You can then separate the model into submodes and steps, and use something like LPub3D to create the instruction manual as a pdf (I haven't tried this myself as it is windows only).

Hope this info helps!

[SylvainLS]

42 minutes ago, NathanR said:

but a few bricks may be missing or out of place.

The few (1040) bricks that are neither in the Official LDraw Library nor the Unofficial one are available at digital-bricks.de.

And as for out of place bricks, there’re none if you use the right ldraw.xml file: 

 

[Mirco Hussmann]

Ok, thank you guys for the tips! I will try it as soon as possible.