Custom LDD bricks and fixes

[leonema]

the new parts installer is very very slow to download and reach 100%
also it completely destroyed my ldd data folder :/
fortunately i did a backup...

so hope Stephan will just let us download the compressed files as before
and could update everything by my own...

Edited November 30, 2025 by leonema

[Takanuinuva]

4 hours ago, leonema said:

the new parts installer is very very slow to download and reach 100%
also it completely destroyed my ldd data folder :/
fortunately i did a backup...

so hope Stephan will just let us download the compressed files as before
and could update everything by my own...

So avoid updating for the time being? Or you think it might just be your computer bugging out?

[leonema]

1 hour ago, Takanuinuva said:

So avoid updating for the time being? Or you think it might just be your computer bugging out?

that's just my experience with it

the exe installer completely delete the content of the ldd appdata folder (so disappeared all my templates and the color palettes... :/ )
and then it's slow to download the necessary data (after 1 hour moved from 20% to 23% [started from 20%] so i stopped the full restore and tried the only last update one that made in few minutes)

both not due to my computer and internet conneciton...

but, of course before you try it, just backup the appdata folder...

Edited November 30, 2025 by leonema

[Takanuinuva]

9 hours ago, leonema said:

that's just my experience with it

the exe installer completely delete the content of the ldd appdata folder (so disappeared all my templates and the color palettes... :/ )
and then it's slow to download the necessary data (after 1 hour moved from 20% to 23% [started from 20%] so i stopped the full restore and tried the only last update one that made in few minutes)

both not due to my computer and internet conneciton...

but, of course before you try it, just backup the appdata folder...

Noted. Best to DM Stephen since they don't seem to follow this topic anymore (As I dm'd them about a previous update and they responded there)

[BrokenEye]

Would it be possible to make it so minifigure hands and other holders can grab on to the edges of flat tiles like 3068 or 14769? I know it's a legal connection, but I also know there's a software limit to the number of different types of connection the same piece can make.

[Stephan]

The update is now correct again. There were two issues with it:

1. The Preferences.ini file was being overwritten with my personal one, overwriting your visible Palettes and settings.

2. There was a folder layer missing, causing an error in the folder structure.

Both these errors are now fixed.

Regarding the slower download speed: both update versions (complete and 20251130) download within 2 minutes on my computer. So it could be due to you internet speed. You can actually still choose to manually download the zip files. Just choose the option "Let me choose" from the installer. That asks for a location on your computer to download the zip files to. Then you can decide for yourself which parts to add.

If you only want the zip files, you can manually download them from my GitHub Releases: https://github.com/stephan3321/LDD-custom-update-releases/releases.

Best is indeed to send me a dm here because I get an e-mail notification of it. Or contact me through CustomLDDUpdates.com.

I've wanted to check this topic every now and then, but just didn't manage to do so .

On 12/1/2025 at 10:02 AM, BrokenEye said:

Would it be possible to make it so minifigure hands and other holders can grab on to the edges of flat tiles like 3068 or 14769? I know it's a legal connection, but I also know there's a software limit to the number of different types of connection the same piece can make.

I thought about this last week. I will make some trials by adding a bar connection to them. I need to check if there will be any collision between connection data.

Edited December 9, 2025 by Stephan

[Zotaxian]

this is the reason why I'm not updating until it's fixed. which is a pain... any fixes yet?

On 8/8/2025 at 6:40 AM, BrokenEye said:

Looks like torsos in old builds are still getting deleted, though the problem is noticeably much less common now. That horrifyingly long list of possible suspects I put together a while back has gotten a heck of a lot shorter. Though for some reason I've got a couple minifigs with no neck or waist accessories that weren't holding anything that have had their torsos disappear anyway, which is a bit of a head-scratcher.

And now the satyr legs (24323) are vanishing from almost every (or possibly every) minifig that features them.

this is the reason why I'm not updating until it's fixed. which is a pain... any fixes yet?

[Stephan]

41 minutes ago, Zotaxian said:

this is the reason why I'm not updating until it's fixed. which is a pain... any fixes yet?

this is the reason why I'm not updating until it's fixed. which is a pain... any fixes yet?

The problem already existed in LDD, with a torso partID being referenced by another assembly. I have never been able reproduce this problem, nor does everyone have this problem. I can only say that if you update ALL torso related files, the issue should not occur. At least that's what other users have been telling me. If that doesn't work, you might want to do a clean install and copy files one by one from the update so you can see what is causing the error. If you share your files with me, I might be able to do this as well at some point.

[Zotaxian]

11 hours ago, Stephan said:

The problem already existed in LDD, with a torso partID being referenced by another assembly. I have never been able reproduce this problem, nor does everyone have this problem. I can only say that if you update ALL torso related files, the issue should not occur. At least that's what other users have been telling me. If that doesn't work, you might want to do a clean install and copy files one by one from the update so you can see what is causing the error. If you share your files with me, I might be able to do this as well at some point.

thanks, just tell me what I need to upload. the "LEGO Digital Designer" folder in roaming, and a file with minifigures that broke after the update?

I don't trust myself with not breaking things further, but I'll try updating again in the meantime.

(if it helps, my current version is https://www.customlddupdates.com/1613256_ldd-update-20240120 and I attempted to install the "complete ldd update package" from this update:
https://www.customlddupdates.com/2548405_ldd-update-20250727 which is how things broke)

[suenkachun]

On 12/9/2025 at 3:38 PM, Stephan said:

The update is now correct again. There were two issues with it:

1. The Preferences.ini file was being overwritten with my personal one, overwriting your visible Palettes and settings.

2. There was a folder layer missing, causing an error in the folder structure.

Both these errors are now fixed.

Regarding the slower download speed: both update versions (complete and 20251130) download within 2 minutes on my computer. So it could be due to you internet speed. You can actually still choose to manually download the zip files. Just choose the option "Let me choose" from the installer. That asks for a location on your computer to download the zip files to. Then you can decide for yourself which parts to add.

If you only want the zip files, you can manually download them from my GitHub Releases: https://github.com/stephan3321/LDD-custom-update-releases/releases.

Best is indeed to send me a dm here because I get an e-mail notification of it. Or contact me through CustomLDDUpdates.com.

I've wanted to check this topic every now and then, but just didn't manage to do so .

Just installed the latest Custom LDD Update using the latest “20251130_v1.0.zip” Folder and discovered several small issues. First, after opening the “251130.lxf” a number of Bricks and Decorations are missing as shown below, LDD also marked some Bricks as Removed.

Next, some of the Sticker Decorations under the Optional “Stickers Rar.rar” Folder are now Misplaced due to Updated UV Maps in this Custom Update, the relevant Bricks for these Decorations at least include 63864, 5091, 5092 and 65676, there might be others too since this Folder remains unchanged in the past few Custom LDD Updates.

Lastly, were the contents of the previous “20250822 v1.0 - fix.rar” Dropbox Download been incorporated into any latest Custom LDD Update Releases, since the old “79393_1.png” seems to be the version supplied in “20251130_v1.0.zip” instead of the new one from “20250822 v1.0 - fix.rar”, thanks.

[Eggyslav]

Question: are all old minifig decorations updated? I've postponed updating ever since the new UV maps were introduced, and now I really want to update, but I'm afraid that my minifigures will get messed up.

[SNIPE]

@Stephan I just had a great idea, can't we make a tool that converts a ldr or lxf model into a custom part, therefore it would act like a submodel, you can specify in the tool if you still want parts of the submodel to be movable or re-color-able, just like how with some LDD parts, you can move/recolor certain sub-parts of them.  If the user just wants a read only submodel then he would just choose to not have any recolor-able or movable parts in the "submodel"

This would help make LDD more usable for large projects.

I think a tool that is within LDD is less clunky than an external tool, the internal tool for LDD also lets you import and export submodels. It basically lists all of the project folders submodels. We can even make the tool open a second instance of LDD and load the submodel as a file with a single instance of the submodel or load the submodel as a regular file again.

templates and groups in LDD suck.

I think I and a friend can inject said tool into LDD but I would need someone else to handle the conversion between LDR/LXF as well as the data format of LDD part files.

Edited January 8 by SNIPE

[Takanuinuva]

Recalling this now. But I like how you were able to change the color menu and add more colors.

Would it be possible to fix the bugs with the texture menu? Along with making some changes to it?

Sometimes it freezes when scrolling making me have to reopen it.
Zoom in to better see the textures (Specifically for Minifig prints)

And maybe change the window so it has to be manually closed when opened. Rather than it closing when your mouse hovers off of the menu.

[BrokenEye]

I notice there are now a couple of decals whose names start with "xx". Do those show up in the program, despite having non-numerical characters? If so, do any other characters work?

[BrokenEye]

Looks like there might be a problem exporting models as Ldraw files. I tried creating an Ldraw file so I could import a model into Blender (since the POV-Ray converter has been abandoned, and I haven't been able to get Bluerender to work with the mod), and a large number of pieces are missing from the render, misplaced, rotated from their original position, or had their color changed. Most of the errors seem to be mod pieces or mod colors, though some aren't (it's possible that the problem is with importing into Blender rather than exporting to Ldraw, but I dunno).

<-- Original LDD model

 <-- Ldraw file in Blender

Edited February 14 by BrokenEye

[Eggyslav]

Guys, you know what should be your main priority Right now? BRING BACK OLD MINIFIG DECORATIONS! PLEASE! I WILL NOT UPDATE UNTILL YOU BRING THEM BACK!

[DraikNova]

Any chance we could get part 41179?

[AnnaS]

I try to use the wheel2a and wheel2b in Bricklink Studio. These are the old spoked LEGO train wheels, available in the Development Version 20210710, the files are 24300 and 24400), but both models are marked as "nullbrick" when I open the appropriate 210710.lxf.

Is there anything I can do about it to use those wheels? I looked around a bit but couldn't find a solution for that problem.

[SylvainLS]

On 6/6/2026 at 5:03 PM, AnnaS said:

I try to use the wheel2a and wheel2b in Bricklink Studio. These are the old spoked LEGO train wheels, available in the Development Version 20210710, the files are 24300 and 24400), but both models are marked as "nullbrick" when I open the appropriate 210710.lxf.

Is there anything I can do about it to use those wheels? I looked around a bit but couldn't find a solution for that problem.

It can’t work this way.

The file 210710.lxf doesn’t contain the 3D model, it just says “eh, I’m using 24300 at this position, oriented this way.”  When you open it in Studio, Studio looks in its conversion table for 24300 and finds nothing… so it uses the NullBrick instead.

For parts that don’t exist in Studio (yet), you need to import them from LDraw through PartDesigner.  See the Parts FAQ on the Studio forum.

For wheel2b, you want this LDraw part.  Its files are actually already in Studio but the part has not been prepared (no connectivity info, no collision info, no ID match in the database).  LDraw doesn’t seem to differentiate wheel2b and wheel2a.

[BrokenEye]

Is there any way to download the latest update as a zip file rather than an installer?

[suenkachun]

12 hours ago, BrokenEye said:

Is there any way to download the latest update as a zip file rather than an installer?

Just go to GitHub and look for the latest release to download as a ZIP File, there are a few minor issues when I installed it around last week (missing Decorations/UV Map Images and seven Bricks glitching slightly but no missing Bricks) but I have already reported these issues from the Update Website Contact Form, the response was they will be looked into and fixed in an upcoming update.

[AnnaS]

On 6/7/2026 at 6:15 PM, SylvainLS said:

It can’t work this way.

The file 210710.lxf doesn’t contain the 3D model, it just says “eh, I’m using 24300 at this position, oriented this way.”  When you open it in Studio, Studio looks in its conversion table for 24300 and finds nothing… so it uses the NullBrick instead.

For parts that don’t exist in Studio (yet), you need to import them from LDraw through PartDesigner.  See the Parts FAQ on the Studio forum.

For wheel2b, you want this LDraw part.  Its files are actually already in Studio but the part has not been prepared (no connectivity info, no collision info, no ID match in the database).  LDraw doesn’t seem to differentiate wheel2b and wheel2a.

Thanks for your help. I loaded the ldd files and added the wheel (minus the metal axle).

[King Azog]

Hi All!

I'm Luca from Italy, an old AFOL.

Can someone explain me how to make decoratable bricks in LDD? Since I'm a very noob, please could you make a step by step tutorial?

Thank you in advance for any help.

Sorry If this reply is not in the proper forum.

Luca

[suenkachun]

1 hour ago, King Azog said:

Hi All!

I'm Luca from Italy, an old AFOL.

Can someone explain me how to make decoratable bricks in LDD? Since I'm a very noob, please could you make a step by step tutorial?

Thank you in advance for any help.

Sorry If this reply is not in the proper forum.

Luca

The first thing to do is make sure the correct latest version of LDD (4.3.11) is installed, then install all Custom LDD Updates released so far, check out this reply for a brief summary. It is slightly more complicated to assign Custom Decoration Surfaces in LDD, so the best thing to do is look for Bricks with one or more Decoratable Surfaces and apply Decorations to these, as Decoration Surfaces are usually enabled depending on whether any Official TLG Decorations use them or not anyway. To check whether a Brick has been made Decoratable in LDD, simply open a new LDD File, insert the relevant Brick(s) and go to the “File” drop-down Menu then “Export Model” or Press “Ctrl+E” on the Keyboard. Select “.lxfml” as the output File Format and open it with Windows “Notepad”. Locate the following row for each Brick (Part 3010 in Bright Red is used as an example). <Part refID="0" designID="3010" materials="21,0,0" decoration="0,0">. As long as “decoration="0"”, decoration="0,0" or similar is present, then it is Decoratable.

LDD accepts Image Files in the “.PNG” Format with Pixels (px) as the Measurement Unit, where the “Bit Depth” of each PNG Image must equal 32 for everything to be displayed properly. The Maximum LDD Decoration Size is 1024 Pixels times 1024 Pixels, while Decoration Sizes which are the Power of 2 (1:2, 1:4 and 1:8) are also accepted (so not 1:3 and 1:6). Simply take the standard LEGO Brick sizes in Centimetres (1 Brick Width 0.8 cm Height 0.96 cm, Plate Height 0.32 cm, Flat Tile Main Height 0.27 cm with 0.05 cm Base Groove total 0.32 cm, etc.) to Scale Up into the required Pixel Measurements by calculating ratios. The following Maximum Decoration Dimensions should always be used: all 1:1 Surfaces: 1024px times 1024px, all 1:2 Surfaces: 512px times 1024px, all 1:4 Surfaces: 256px times 1024px, all 1:8 Surfaces: 128px times 1024px. For all non-Power of 2 and Irregular Surfaces always use the Maximum Square 1024px times 1024px, some newer official LEGO Decorations added in recent Custom LDD Updates still use slightly Smaller Dimensions of all 1:1 Surfaces 512px times 512px and all 1:2 Surfaces: 256px times 512px, but the Maximum Dimensions are always preferred since “Larger Decoration Sizes will produce better display results”. Starting from recent Custom LDD Updates, specific UV Maps supplied as PNG Images are also introduced. Located in the “UV Map” Folder supplied with Custom LDD Updates under “db\Decorations”, they explain how to Decorate common LDD Brick Surfaces. Up to the Custom LDD Update on May 10, 2026 there are over 1,100 of these provided with 38 more Complex Surfaces using the “Adobe Photoshop Format” “.psd” plus a “21019 instructions.txt” which explains how to correctly Decorate Part 21019 Mini Lower Part No. 2 (Minifigure Legs), with the following two main groups of PNG UV Maps.

The first group still Decorate individual Brick Surfaces one at a time or only each has one main Decoratable Brick Surface, where the old Maximum Decoration sizes are still used. For Irregular Decorations in this group there are two ways to Decorate: If these Single Surfaces are still using the old Format of accepting a Maximum Square Decoration of 1024px times 1024px, simply Scale Up the Decoration until the Shorter Side equals 1024px and Compress the Longer Side to 1024px; for other Decoration sizes Scale Up the Longer and Shorter Side to 1024px separately then use the result closest to the PNG UV Map Measurements usually Measured in “Microsoft Paint” (e.g., for the Top Main Surface of Part 6636 Flat Tile 1×6, Scale Up To 170.666667px times 1024px, Enlarge the Shorter Height slightly to 172 Pixels and Align to the Centre and Middle of a Plain/Transparent Maximum 1024px times 1024px Square for Output).
The second group of Bricks can now Decorate Multiple Brick Surfaces at once within the same UV Map, so no need to manually apply up to four or five Decoration Surfaces in LDD. Simply Measure all individual Surface and Gap Dimensions in “Microsoft Paint”, then also Scale Up the Longer and Shorter Side to 1024px separately and use the result closest to the UV Map Measurements to further Enlarge or Compress the required Side.

If any PNG UV Map Image does not use the Maximum Decoration Dimensions listed above, it is still possible to manually Scale Up everything until these Maximum Measurements.

Each time a new Custom LDD Update is released, the relevant “Update Overview” Contents found under each Update Post on “https://www.customlddupdates.com/” and in the “Change Log” Plain Text File supplied with each Update will always mention Updated UV Mappings and new Bricks made Decoratable, so check these too. If a UV Map is updated, most likely original Decorations will no longer fit which requires further adjustments. The next thing to do is locate the Text File handling LDD Decorations, navigate to “C:\Users\Username\AppData\Roaming\LEGO Company\LEGO Digital Designer\db” and open the “DecorationMapping.xml” with Windows “Notepad”, the current format used is as follows.
    <Mapping decorationID="XXXXXX" designID="YYYYY" surfaceID="Z"/>
To add Custom Decorations, simply add more entries after the current ones using the same format as above (also add blank rows to make a new Section). Each time a new Custom LDD Update is released the original “DecorationMapping.xml” will most likely be updated with new entries, so remember to manually add back all Custom entries whenever this File is updated. The “decorationID” is a unique Number assigned to each LDD Decoration, usually a five- or six-digit Number. Most of these are obtained from TLG’s official Database itself, but a Custom Decoration ID can always be assigned if no Official Decorations are using that particular Number. Unfortunately, there is no way to guarantee that these will not be used by an Official Decoration in the future which will then be overwritten, the only best thing to do is to use six Numbers and try to stay away from the 1XXXXX range but this is still not completely safe. The “designID” refers to the Part Number of the Brick in the LDD Database, also obtained from TLG’s official Database itself, which is a fixed four-, five- or six-digit Number. The “surfaceID” refers to the Decoratable Surface(s) of the corresponding Brick. Most Bricks with only one Main Decoration Surface will only use “1”, but some can actually have more than one.

To create Custom LDD Decorations, simply use the PNG UV Map Images as a starting point and design using these Measurements and Layouts. After much research, the best Format to use during the design process is the “Scalable Vector Graphics (SVG)” Format instead of Bitmaps, where infinite scaling without Pixelation is possible for SVG and exact Circles/Curves/Slopes no longer Pixelated can be Drawn accurately. Once complete, Name it using the “decorationID” Rules above, Save it soemwhere then Copy and Paste into the LDD Decoration Folder located in “C:\Users\Username\AppData\Roaming\LEGO Company\LEGO Digital Designer\db\Decorations”. Once a Custom Decoration has been successfully added to the LDD Database, simply open a new LDD File and go to “LDD Extended”, insert the relevant Brick in the desired Colour then use the “Decoration tool” to select the relevant Brick Surface and manually select the Decoration from the list to apply it. Alternatively, temporarily convert any LDD “.lxf” File into a “.lxfml” File and add the Decorations directiy with Windows “Notepad”, one Brick benefiting greatly from this method is the Minifigure Torso (Part 3814) where the long list of tiny Images within the “Decoration tool” and the Scroll Feature not always working (both cannot be fixed right now) may lengthen the time required to locate the wanted Decorations. For the second method: Locate the “.lxf” File such as “1234.lxf” and temporarily change its File Extension from “.lxf” to “.zip” thus becoming “1234.zip”; unzip “1234.zip” which creates a new Folder “1234” in the same Folder as “1234.zip”, then open “1234” which should contain two Files “IMAGE100.LXFML” and “IMAGE100.PNG” (as these two File Names will be universal across each converted “.lxf” File, please convert one at a time); open “IMAGE100.LXFML” with Windows “Notepad” and locate the relevant Brick to Decorate, then update the “decoration="0"”, decoration="0,0" or similar section by replacing each “0” with the relevant Decoration Number; once all relevant Bricks have been updated, close “IMAGE100.LXFML” then Copy both “IMAGE100.LXFML” and “IMAGE100.PNG” to Paste both Files within “1234.zip”, always selecting “Copy and Replace” for both when promoted; Delete the “1234” Folder and change “1234.zip” back into “1234.lxf”, then open in LDD as usual with all Decorations successfully applied.

Hope this information helps.

[King Azog]

10 minutes ago, suenkachun said:

The first thing to do is make sure the correct latest version of LDD (4.3.11) is installed, then install all Custom LDD Updates released so far, check out this reply for a brief summary. It is slightly more complicated to assign Custom Decoration Surfaces in LDD, so the best thing to do is look for Bricks with one or more Decoratable Surfaces and apply Decorations to these, as Decoration Surfaces are usually enabled depending on whether any Official TLG Decorations use them or not anyway. To check whether a Brick has been made Decoratable in LDD, simply open a new LDD File, insert the relevant Brick(s) and go to the “File” drop-down Menu then “Export Model” or Press “Ctrl+E” on the Keyboard. Select “.lxfml” as the output File Format and open it with Windows “Notepad”. Locate the following row for each Brick (Part 3010 in Bright Red is used as an example). <Part refID="0" designID="3010" materials="21,0,0" decoration="0,0">. As long as “decoration="0"”, decoration="0,0" or similar is present, then it is Decoratable.

LDD accepts Image Files in the “.PNG” Format with Pixels (px) as the Measurement Unit, where the “Bit Depth” of each PNG Image must equal 32 for everything to be displayed properly. The Maximum LDD Decoration Size is 1024 Pixels times 1024 Pixels, while Decoration Sizes which are the Power of 2 (1:2, 1:4 and 1:8) are also accepted (so not 1:3 and 1:6). Simply take the standard LEGO Brick sizes in Centimetres (1 Brick Width 0.8 cm Height 0.96 cm, Plate Height 0.32 cm, Flat Tile Main Height 0.27 cm with 0.05 cm Base Groove total 0.32 cm, etc.) to Scale Up into the required Pixel Measurements by calculating ratios. The following Maximum Decoration Dimensions should always be used: all 1:1 Surfaces: 1024px times 1024px, all 1:2 Surfaces: 512px times 1024px, all 1:4 Surfaces: 256px times 1024px, all 1:8 Surfaces: 128px times 1024px. For all non-Power of 2 and Irregular Surfaces always use the Maximum Square 1024px times 1024px, some newer official LEGO Decorations added in recent Custom LDD Updates still use slightly Smaller Dimensions of all 1:1 Surfaces 512px times 512px and all 1:2 Surfaces: 256px times 512px, but the Maximum Dimensions are always preferred since “Larger Decoration Sizes will produce better display results”. Starting from recent Custom LDD Updates, specific UV Maps supplied as PNG Images are also introduced. Located in the “UV Map” Folder supplied with Custom LDD Updates under “db\Decorations”, they explain how to Decorate common LDD Brick Surfaces. Up to the Custom LDD Update on May 10, 2026 there are over 1,100 of these provided with 38 more Complex Surfaces using the “Adobe Photoshop Format” “.psd” plus a “21019 instructions.txt” which explains how to correctly Decorate Part 21019 Mini Lower Part No. 2 (Minifigure Legs), with the following two main groups of PNG UV Maps.

The first group still Decorate individual Brick Surfaces one at a time or only each has one main Decoratable Brick Surface, where the old Maximum Decoration sizes are still used. For Irregular Decorations in this group there are two ways to Decorate: If these Single Surfaces are still using the old Format of accepting a Maximum Square Decoration of 1024px times 1024px, simply Scale Up the Decoration until the Shorter Side equals 1024px and Compress the Longer Side to 1024px; for other Decoration sizes Scale Up the Longer and Shorter Side to 1024px separately then use the result closest to the PNG UV Map Measurements usually Measured in “Microsoft Paint” (e.g., for the Top Main Surface of Part 6636 Flat Tile 1×6, Scale Up To 170.666667px times 1024px, Enlarge the Shorter Height slightly to 172 Pixels and Align to the Centre and Middle of a Plain/Transparent Maximum 1024px times 1024px Square for Output).
The second group of Bricks can now Decorate Multiple Brick Surfaces at once within the same UV Map, so no need to manually apply up to four or five Decoration Surfaces in LDD. Simply Measure all individual Surface and Gap Dimensions in “Microsoft Paint”, then also Scale Up the Longer and Shorter Side to 1024px separately and use the result closest to the UV Map Measurements to further Enlarge or Compress the required Side.

If any PNG UV Map Image does not use the Maximum Decoration Dimensions listed above, it is still possible to manually Scale Up everything until these Maximum Measurements.

Each time a new Custom LDD Update is released, the relevant “Update Overview” Contents found under each Update Post on “https://www.customlddupdates.com/” and in the “Change Log” Plain Text File supplied with each Update will always mention Updated UV Mappings and new Bricks made Decoratable, so check these too. If a UV Map is updated, most likely original Decorations will no longer fit which requires further adjustments. The next thing to do is locate the Text File handling LDD Decorations, navigate to “C:\Users\Username\AppData\Roaming\LEGO Company\LEGO Digital Designer\db” and open the “DecorationMapping.xml” with Windows “Notepad”, the current format used is as follows.
    <Mapping decorationID="XXXXXX" designID="YYYYY" surfaceID="Z"/>
To add Custom Decorations, simply add more entries after the current ones using the same format as above (also add blank rows to make a new Section). Each time a new Custom LDD Update is released the original “DecorationMapping.xml” will most likely be updated with new entries, so remember to manually add back all Custom entries whenever this File is updated. The “decorationID” is a unique Number assigned to each LDD Decoration, usually a five- or six-digit Number. Most of these are obtained from TLG’s official Database itself, but a Custom Decoration ID can always be assigned if no Official Decorations are using that particular Number. Unfortunately, there is no way to guarantee that these will not be used by an Official Decoration in the future which will then be overwritten, the only best thing to do is to use six Numbers and try to stay away from the 1XXXXX range but this is still not completely safe. The “designID” refers to the Part Number of the Brick in the LDD Database, also obtained from TLG’s official Database itself, which is a fixed four-, five- or six-digit Number. The “surfaceID” refers to the Decoratable Surface(s) of the corresponding Brick. Most Bricks with only one Main Decoration Surface will only use “1”, but some can actually have more than one.

To create Custom LDD Decorations, simply use the PNG UV Map Images as a starting point and design using these Measurements and Layouts. After much research, the best Format to use during the design process is the “Scalable Vector Graphics (SVG)” Format instead of Bitmaps, where infinite scaling without Pixelation is possible for SVG and exact Circles/Curves/Slopes no longer Pixelated can be Drawn accurately. Once complete, Name it using the “decorationID” Rules above, Save it soemwhere then Copy and Paste into the LDD Decoration Folder located in “C:\Users\Username\AppData\Roaming\LEGO Company\LEGO Digital Designer\db\Decorations”. Once a Custom Decoration has been successfully added to the LDD Database, simply open a new LDD File and go to “LDD Extended”, insert the relevant Brick in the desired Colour then use the “Decoration tool” to select the relevant Brick Surface and manually select the Decoration from the list to apply it. Alternatively, temporarily convert any LDD “.lxf” File into a “.lxfml” File and add the Decorations directiy with Windows “Notepad”, one Brick benefiting greatly from this method is the Minifigure Torso (Part 3814) where the long list of tiny Images within the “Decoration tool” and the Scroll Feature not always working (both cannot be fixed right now) may lengthen the time required to locate the wanted Decorations. For the second method: Locate the “.lxf” File such as “1234.lxf” and temporarily change its File Extension from “.lxf” to “.zip” thus becoming “1234.zip”; unzip “1234.zip” which creates a new Folder “1234” in the same Folder as “1234.zip”, then open “1234” which should contain two Files “IMAGE100.LXFML” and “IMAGE100.PNG” (as these two File Names will be universal across each converted “.lxf” File, please convert one at a time); open “IMAGE100.LXFML” with Windows “Notepad” and locate the relevant Brick to Decorate, then update the “decoration="0"”, decoration="0,0" or similar section by replacing each “0” with the relevant Decoration Number; once all relevant Bricks have been updated, close “IMAGE100.LXFML” then Copy both “IMAGE100.LXFML” and “IMAGE100.PNG” to Paste both Files within “1234.zip”, always selecting “Copy and Replace” for both when promoted; Delete the “1234” Folder and change “1234.zip” back into “1234.lxf”, then open in LDD as usual with all Decorations successfully applied.

Hope this information helps.

Thank you very much. This response goes far beyond my expectations. A lot to read. just another question or example: if I wanted to make item 3754 BRICK 1x6x5 (that has not "decoration=0" string in the lxmf file), how should I proceed? Thank you very much indeed.