When I go through these LEGO kit instructions (as an example)


I get the list of all parts and part numbers at the end of the PDF pages:

Parts list from instructions

None of the part numbers in the above list are recognised by the LDD. LDD had different part numbers. Why is that?

Is there any easy way to convert part numbers mentioned in the instruction PDFs to the LDD part numbers? Or is there any easy way to have LDD recognize the part numbers in the instruction PDFs?

Update 1:

All of the parts in the 42061 kit are available in LDD, with different part#. You can see for yourself by taking a look at its LXF file available for download here:


1 Answer 1


The two different number systems are:

  • Element ID: 6-7 digits, uniquely identifies a piece by shape and color
  • Part number: usually 4-5 digits, uniquely identifies a piece shape, stamped on many bricks

(Unfortunately an element ID is not simply a few numbers added onto a part number)

In LDD regular mode (not extended mode), you can search by both numbers. I was able to find the 3L blue pins by searching both element ID 4514553 and part number 6558. When in extended mode however you can only search by part number (many of those pieces listed are only in extended mode).

Generally, you can also search for an element ID on BrickLink and find the part number. Not sure about going the other way.

  • Please see the Update 1 I added to my post. All of the kit#42061 parts are available in LDD, with a different part number.
    – Allan Xu
    May 31, 2018 at 20:33
  • @AllanXu Yeah, you're right. Turns out extended mode works differently. I've updated my answer. May 31, 2018 at 20:38

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