I’d like to build a MOC of a Technic vehicle that was posted online using the provided LXF file of the completed model.

I was able to open the LXF file with both Bricksmith and Stud.io, but, as far as I can tell, it is not broken down into a sequence of assembly steps. In other words, both programs shows just the completed model.

I’d like to know either: (A) how to view the intended/embedded step-by-step instructions, assuming they exist, and/or (B) if there is a common/best practice for manually determining an assembly order when all you have is a completed model in an LXF file.

FYI, the model I want to build is the awesome looking Chili Crawler by PunkTacoNYC. It can be seen on YouTube, and the LXF file is available here.


The LXF file contains the complete model as created with Lego Digital Designer (the Lego CAD tool from The Lego Company). The model usually doesn't require to have building steps as they are (always) automatically generated from the model.

For normal, non-Technic models, Lego Digital Designer (LDD) is able to create automated building instrutions. My experience with LDD and Technic models / MOCs is that you have good support for designing the completed model, but that for the generation of building instructions you're better off with other tools.

You can translate an existing LXF file into an LDraw model (file extension: .ldr), but for some exotic (read: Technic) parts, the translation of LDD parts and LDraw parts is either incomplete or has problems with part orientation. This means that you may have to do manual edits to your model in order to have an (almost) complete translation into LDraw file format. See e.g. this site for details.

One advantage of the LDraw format, is that you can define "building steps" and sub assemblies in the design, which makes the generation of complex building instructions easier.

A tool for creating building instructions from a LDraw model, is LPub3D. Otherwise I'd suggest using a Lego CAD tool such as LDCad.

  • I did end up converting the LXF file to a Stud.io file, which, like LDraw, allows the creation of steps. I could see instructions in Lego Digital Designer, but the steps were not in the proper order. That makes efficient Technic building painful, if not impossible. As far as a ‘best practice’, which was part of my question, I suspect one is methodically disassembling the CAD model, which appears to create building steps in reverse. I wonder if this method has worked for anyone else — or if it hasn’t. – EJ Mak Jan 10 '18 at 16:37

Starting from LDD files and LXF, a good software is Blueprint from msx80


With this, you can organise how you want the pieces to get assembled (by default the auto-generated steps are not always optimal), then export a PDF, I think it's pretty great.


You can use LDD (Lego Digital Designer) the official LXF viewer by Lego. This allows you to create building instructions to view or export to html.

You can also use this software to build models, and i find it much better than other softwares since it is simple, with easy UI.

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