@Grice

It's not gone.
The link doesn't work, because a while ago Fredo merged many of his smaller extensions into FredoTools.
This includes dozens of useful tools...
You can install that set from the PluginStore via a downloaded RBZ
https://sketchucation.com/pluginstore?pln=FredoTools
Or use the SketchUcation ExtensionStore³ tool to install it, without the RBZ step...

@hafizhasan99
Please don't create multiple post-threads on the same subject.
I've deleted the duplicates...
I'm sure someone will respond [@Curic ?]

@MarieEve-Martel

To find your Plugins folder do the following...
Open the Ruby Console from Extensions > Developer...
In its bottom a pane type or copy/paste this line of code.
Sketchup.find_support_file('Plugins')
It should return the path to the folder...
Use that to find/navigate to your Plugins folder...

If you have the SketchUcation tools installed there is a submenu item...
Extensions > SketchUcation > Open Plugins Folder...
Clicking on this opens your Plugins folder - so it's less of a hassle...

@MarieEve-Martel
If you read the old 'help' posts...
Open the RB file in your Plugins folder, using a plain-text editor [not a wordprocessor]
Find the line...
@grad_dialog.add_action_callback("get_data") do | @grad_dialog, action_name |
change it to
@grad_dialog.add_action_callback("get_data") do | grad_dialog, action_name |
Save it back into your Plugins folder.
After a restart SketchUp should load the good code...

@vineeta1007
Please open the Ruby Console [Extensions > Developer submenu item]
Then try the tool again and see if there are any error messages...
Report back...
Do you have the newest versions of LibFredo6 and the SketchUcation toolset installed ?
Have you activated the license from the file you got and restarted ? The license management section is under the Tools menu entry for that extension...

@dahnuguy
The model.save_copy method is only available >=v2014
So it fails in v8.

@NeukJullie
Sometime ago many of Fredo's extensions became licensed.
So to continue to use it beyond the trial period you need to install the latest version of his LibFredo6 and the SketchUcation tools [for the licensing]
It is not expensive, and there's a bundle of several of his extensions offering savings.
Also SCF Premium members get further discounts...

There are many posts about this...

@SergioAlbelli
In addition to Rich's useful info...
We are assuming you have bought a license for Fredo's RoundCorner extension and not his other FredoCorner extension, whatever, then you need to save its file onto your computer and then validate it in the appropriate dialog opened from that extension's submenu in the Tools menu...
There are pages to help you mange your licenses as listed in this thread...
We need more info if you still can't resolve it...

@chris341

It is a very old thread !
I've fixed the basic syntax errors and added modules etc.
It works in v2024 [should be OK in v2020] - but I'm unsure of its efficacy...
Aerilius_UV_realign_uvs.rb

@November11
Follow the message's instructions on opening the folder and deleting the file.
You might need to rename your computer...

Your computer-name must follow the Windows rules - i.e. NO special characters in it...
This is a range of characters that can be considered safe:
Letters (a-z A-Z)
Digits (0-9)
Underscore (_)
Hyphen (-)
Space
Dot (.)
Beyond this, you just have to enforce some additional rules regarding spaces and dots. This is usually sufficient:
Name must contain at least one letter or number (to avoid only dots/spaces)
Name must start with a letter or number (to avoid leading dots/spaces)
Name may not end with a dot or space

Do you have any special characters in the computer-name OR your user-name ? - I guess you are Chinese ?

Try fixing that and restart to see if that helps...
Let us know how you get on...

@Anonimos24

You are sorely mistaken.
It is not a 'scam'.
Fredo and this site are highly regarded.
The reason you can't use it, is that it relies on a 'Lib' - LibFredo6.
It is clearly spelled out on its download page...
The error message even gives you a link to get it [you need to answer 'Si'].
After it's been downloaded and installed, restart SketchUp so that everything gets synced.
It will need licensing after a trial so you also need the SketchUcation tools installing for this...

Estás muy equivocado.
No es una 'estafa'.
Fredo y este sitio gozan de gran prestigio.
La razón por la que no puedes usarlo es que depende de una 'Lib': LibFredo6.
Está claramente explicado en su página de descarga...
El mensaje de error incluso te da un enlace para obtenerlo [debes responder 'Si'].
Una vez descargado e instalado, reinicia SketchUp para que todo se sincronice.
Necesitará una licencia después de una prueba, por lo que también necesitará instalar las herramientas SketchUcation para esto...

@seabreezemojito
Firstly: did you restart SketchUp after the installation ? It's needed to sync Fredo's tools with his Lib etc.
Secondly: do you have the latest versions of Fredo6Lib and SketchUcation tools installed ?

@parkjh1477

Both versions can exists side-by-side, so don't delete v2021 just yet.
Does your computer-name follow the Windows rules - i.e. no special characters...
This is a range of characters that can be considered safe:
Letters (a-z A-Z)
Digits (0-9)
Underscore (_)
Hyphen (-)
Space
Dot (.)
Beyond this, you just have to enforce some additional rules regarding spaces and dots. This is usually sufficient:
Name must contain at least one letter or number (to avoid only dots/spaces)
Name must start with a letter or number (to avoid leading dots/spaces)
Name may not end with a dot or space

Do you have any special characters in the computer-name OR your user-name ? - I guess you are Korean ?

@parkjh1477

The error message means the signature file can't be read.
You can follow the instructions and delete the file [folder opens on button click], then re-validate the licenses and see if that helps...
This can happen if you change the name of your computer, it can also be affected if you have computer name that doesn't follow the Windows rules - e.g. the computer's name contains special characters causing issues with the licensing system saved data...
Let us know how you get on...

@hmurphy

Have you restarted SketchUp after the extension / lib were installed ?
That should sync everything.
The toolbar & menu items should show up then.
Fredo's extensions are listed under a submenu in the Tools menu... did you look there after a restart ?
Simply paying for a license doesn't license the extension. You need to activate it in the appropriate submenu under Tools...
If you have tried all of this without success, then please comeback for further help...

@djh
They might have the same names but they are in different locations - e.g. the Exporters and Importers folder...
I do not recommend that you remove them.
Doing so might not cause an issue immediately because they might be loaded by another application earlier, but why risk it ? Your OCD should be kept in check. You could probably find hundreds of 'duplicate' files on your computer - let sleeping dogs lie.

@Gábor

An odd title indeed...

According to GoogleTranslate...
This [аываырпукфрерп] refers to generally good things... e.g.

'Thanksgiving' in many diverse languages...

e.g. in Assamese from NE India... OR Aymara from the Bolivian Andes... OR Bambara from Mali in Africa... OR Bhojpuri from that India and Nepal... OR Dhevehi from the Maldives... OR Dogri from Jammu and Kashmir [India]... OR Ewe / Twi from Ghana and Togo... OR Guarani from Paraguay... OR Ilocano from the Philippines... OR Konkani from Western India... OR Krio from Sierra Leone... OR Sorani Kurdish... OR Lingala from the Congo [Bantu]... OR Luganda from the African central lakes... OR Maithili from India and Nepal... OR Meitei / Manipuri / Mizo from Tibet and NE India... OR Oromo from Ethiopia / Kenya... OR Quechuan from Peru and the Andes... OR Sanskrit the ancient language from the Indian subcontinent... OR Sepedi [Sotho] / Tsonga from NE South Africa... OR Tigrinya from Tigray...

OR it could mean 'Andhra Pradesh' [SE India] in simplified Chinese...
OR it could mean 'Ayurvedic Medicine' in Hindi...
OR it could mean 'Pain Free' in Tatar...
OR it could mean 'Don't Worry' in Turkmen...
OR it could mean 'The Difference' in Uryghur [Turkic Central Asia]...

But I suspect it's just a gibberish title that coincidentally has some meaning[s]...
I think your answer will resolve it !

@guanjin
It doesn't work in v2024 [various errors], e.g.

Error: #<NoMethodError: undefined method 'index' for {#Sketchup::Edge:0x0000019daaeab1b0=>0.0, #Sketchup::Edge:0x0000019daaeab160=>39.37007874015748}:Hash>
C:/Users/TIG/AppData/Roaming/SketchUp/SketchUp 2024/SketchUp/Plugins/GEIS_door_lintel2.rb: 100:in 'dbe_by_embrasure'
C:/Users/TIG/AppData/Roaming/SketchUp/SketchUp 2024/SketchUp/Plugins/GEIS_door_lintel2.rb: 274:in `block in <top (required)>'

@Didier-Bur also obfuscates his code, so without arduously repacking it back into RB code it'd be difficult to say what the issues are...

@Finito86
The Plugins folder's permissions look OK...

SketchUcation.rb is loading OK
but
../PluginsSketchUcation/SCF_loader.rbe is not loading OK.

Please look at the ../Plugins/SketchUcation folder's Properties/Edit and check all entries have 'Full Control'...
Changes to the Plugins folder's Properties should filter down to all of the contents...
Also check that its RBE files have 'Full Control' and 'read' properties set - if not adjust them to suit...

Perhaps @Gabor has some ideas ?

@brittico
Are there other options like 'url' ?
The string given is not a file-type...