The brick runners (e.g.  31202c04) are assemblies consisting of one base, four wheels, and two axles.

The base has 31202 embossed onto it and 5436 printed with black ink.
Each wheel has 31204 embossed on it.
The metal axles have no visible part numbers.

What is the part number for the chassis/base to be used in LDraw?
What is the assembly number to be used in LDRaw?
Shall the c01... follow the same logic as in BrickLink?
What u number can I use for the metal axles and which color would I make it?

Is there any special way to mark these parts as members of assemblies/shortcuts so that they do not get used outside any assembly?

I'd like to ressurect this discussion:
https://forums.ldraw.org/thread-28281-post-54224.html

To recap, the current practice is as follows:
- The part and the sticker should be color 16
- If the part is an assembly of a color 16 part and a transparent part and the sticker is placed on the transparent area:
  - For a solid color sticker, the color will be the color of the sticker back (usually white)
  - For a transparent sticker, the color will be Trans_Sticker

I'm advocating that all stickers in a sticker shortcut should be hard coded the color that they actually are.

In fact, I'm also leaning towards the notion that all sticker colors should be hard coded in the sticker itself (i.e. no color 16 boxes but white, clear, sliver, etc.). This would clear up a lot of problems but not sure we need to go that far.

No matter which part I click on in the Parts List I get the "500 | SERVER ERROR" message.  But was able to download the part file.

LDConfig made from the one in the LDraw.org 2025-07 Parts Update.
This is a LDConfig file that includes the "Render Only" colours from Bricklink Studio.
(Without LUMINANCE values, I might change that in future updates)

To use it do the following:

1. Download it:
     LDConfig_plus_bl_studio_colours.ldr (Size: 55.49 KB / Downloads: 7)
   
2. Move it to your LDraw folder
   
3. Rename "LDConfig.ldr" to LDConfig_default.ldr(or something else)
   
4. Rename "LDConfig_plus_bl_studio_colours.ldr" to "LDConfig.ldr"
   

The 2025-07 LDraw Parts Update has been released. This update adds 448 new files to the core library, including 263 new parts and 6 new primitives.

Thanks are due to all the part authors who created or corrected parts for this release. The small, but dedicated, band of reviewers also play an important role in keeping files moving through the Parts Tracker and deserve just as much credit. This update wouldn't have been possible without their dedication and attention to detail.

You can preview the new parts in 2025-07 here, and download the zip-file update or Windows install package here.

Thank you to all the testers and parts authors who continue giving feedback on the PT software. This project would not be what it is without your help.

Orion Pobursky
Magnus Forsberg
Gerald Lasser
LDraw.org Parts Library Admins

Hi,

I am trying to create a phone app, and my goal is to show each step of my design (with LDCad) on the phone app the same way as shown in LDCad. I met a problem when implementing the behavior when a step rotating on Z.

Below is a step having no rotation:


But when I just rotate it around Z for 30 degrees, it is rendered like this:


From what I see, it is more like rotating on Y and X for some reason. But if I open the same step in LPub3D, the render is expected as below:



Could anyone help me to understand what is the logic behind this in LDCad? Or can it just be a bug?

Thanks!

The Duplo cannons are composed of multiple physical pieces screwed together. Looking specifically on the cannon with locking ring and red button 17178c01 or 94886c01.

What is the minimum that need to be modeled?

Some motors, projectile launchers, and springs have been modeled down to each screw and separable part even if that has meant the creation of (sub)parts with u numbers. Obtaining subpart numbers and internal structure requires opening the assembly, possibly destroying its play-ability in the process.

Rubber insets are sometimes modeled only by their visible parts.

Can the firing button be modeled as a red surface or does it need to be a separate subpart?

How accurately does the internal structure (metal spring and projectile guides) need to be modeled?

Do the screws need to be modeled as separate parts?

Hi,

this version gives you just a pair of small improvements.



As always, you can download LDPE from this page:

http://nilsschmidt1337.github.io/ldparteditor/

Changelog:

(1 new feature and 1 bug fix)

With this release you will be able to...

• ...see a hint if the part type does not match to its name.
  

1. A recurring subpart reference loop can cause the program to crash or hang.
   

1. Download and extract LDPartEditor_win32_x64.zip
   
2. Run LDPartEditor-1.8.95.msi
   
3. Start LDPartEditor from the start menu
   

1. Download and extract LDPartEditor_linux_x64.zip
   
2. Install ldparteditor_1.8.95-1_amd64.deb
   
3. Start LDPartEditor from the menu or via launcher
   

1. Download and extract LDPartEditor_mac_x64.zip
   
2. Mount LDPartEditor-1.8.95.dmg
   
3. Drag LDPartEditor.app to the Applications folder
   
4. Copy ldparteditor.sh to your home folder
       4a. Open a Terminal.app and run ./ldparteditor.sh
       4b. Or open a Terminal.app and run /Applications/LDPartEditor.app/Contents/MacOS/LDPartEditor
   

• OpenGL 2.1 compatible Graphics Card
  
• Operating System (64-bit): Windows [7 or newer], Linux [e.g. Ubuntu Linux >=14.4], Mac OS X [>=10.6]
  
• CPU: Multicore-Processor e.g. Intel Core 2 Duo or AMD Athlon II (>2.0Ghz)
  
• RAM: 4GB
  
• Video-Memory: 1 GB
  
• Free Disk Space: 150 MB
  

• Operating System (64bit): Windows 7,8,10,11, Linux [e.g. Ubuntu Linux >=14.4], Mac OS X [>=10.6]
  
• OpenGL 3.3 compatible Graphics Card
  
• CPU: Multicore-Processor with 4 cores (or more)
  
• RAM: >4 GB
  
• Video-Memory: >1 GB
  
• Free Disk Space: 500 MB
  
• For a faster start, LDPartEditor and the LDraw™ library should be installed on an SSD.
  

BrickLink lists two duplo cannon balls:
54043 Duplo Cannon Ball 1/2 with Large Axle Connector
54043b Duplo Cannon Ball 1/2 with Large Axle Connector and 4 Holes in Top
These parts have visibly different geometry, the newer is more reinforced and has 4 holes.

How should they be numbered in LDraw? Keep 54043 and 54043b or go with a and b versions?

I've long struggled with parts that have two curved edges close to each other, but not having the same point of origin. The task is to fill in the area between the curves.

If the curves are far enough apart, I can use tndis and chords. However, if they are close, then I'd have to rotate chords and tndises, which isn't ideal.

Luckily, we have tang for the inside (in yellow). This eliminates the need to rotate ndises, but effectively doubles the number of points. If the inside and the outside of an area to be filled have significantly different number of points, then the result is a large amount of extremely narrow triangles, so this is to be avoided.

What if we had an inverse tang (in black) to be used for the outside? With an equal number of points, it is easy to fill the light gray area with quads.