After sharing the guide with friends, there were still a few misunderstandings, so the guide has been reworked to be more comprehensive. The surface types section is in a incomplete state, and is open for further criticism. As I ended up prioritizing appearance (and yes, I know about glue surface type).
Also, re-read OP since you seem a bit invested in it. Cheers. @KingBlueDash
Surface types are now complete, and more examples have been added in the “Part Type” and “Author Notes” sections. That’s all for now o7.
Is there a working download for Mark Alsip’s skyboxes?
I don’t think the downloads are archived for Mark Alsip’s skyboxes, but if you’re looking for more skyboxes, you can check the one created by Rombom when he was a forum moderator back in 2007 who uploaded other skyboxes belonging to Mark Alsip’s site and some other stuff, I’ll re-upload it, put it in google doc and OP.
https://create.roblox.com/store/asset/108743092193471/Alien-Harbor-Skybox
https://create.roblox.com/store/asset/73737952108384/Ammonia-Skybox
https://create.roblox.com/store/asset/115749850572333/Armegeddon-Skybox
https://create.roblox.com/store/asset/110647969895287/Backlit-Skybox
https://create.roblox.com/store/asset/88473811492122/Clear-Grey-Skybox
https://create.roblox.com/store/asset/72443200622092/Cold-w-mountains
https://create.roblox.com/store/asset/75260239981592/Light-Blue-Skybox
https://create.roblox.com/store/asset/74651702873710/Mysterious-Skybox
https://create.roblox.com/store/asset/107257505430848/Onimous-Skybox
https://create.roblox.com/store/asset/127581315250671/Random-Skybox
https://create.roblox.com/store/asset/133154146467731/Summer-Day-Skybox
https://create.roblox.com/store/asset/74829495982134/Yeller-Skybox
Other skyboxes that appear to belong to Mark Alsip.
https://create.roblox.com/store/asset/107707022762708/autumnday1
https://create.roblox.com/store/asset/94831321187073/summerday1
https://create.roblox.com/store/asset/127575046313619/violet02
https://create.roblox.com/store/asset/89001314806779/antarctica
https://create.roblox.com/store/asset/136868402397717/parfait
https://create.roblox.com/store/asset/132503658233433/Sunny-Sky
https://create.roblox.com/store/asset/87195549252016/Summer-Day-4
These skyboxes originate from a 3D racer game, which also belong to Mark Alsip.
Thank you for these! 
THIS IS HIDDEN TEXT. MY SUMMARY: EPIC SKYBOX
Also we need additional designs for UI to make look liking classic also we need this
This will focus solely on building iterations of classic style. My suggestion is to conduct intensive research on a specific year (for example, focusing entirely on 2008, not 2007), rather than generalizing across multiple years for the UI.
As you can see below, the 2007 version has no bevels, and the fonts are significantly different from the 2008 version. There’s also some post-processing, in case you didn’t notice.
Unlike the 2008 version, this one has bevels and a different type of font from the 2007 version. However, it does not include any post-processing.
Using your eyes for observation is a gift to the human body—so use them. (Worst quote of the year, by me.)
Three of my games are now uncopylocked if anyone is interested in checking out!
For skyboxes, I found Terragen Classic great for nailing that Classic Roblox aesthetic given enough fine tuning. I think it’s worth a mention in the google doc for those that want to make their own skyboxes from scratch. I’m pretty sure some user-made skyboxes were made with Terragen as well.
I stumbled upon it a few months ago (link below) trying to find a free alternative to Bryce 7 after watching this video on classic Roblox’s skyboxes. I’m really happy with my results after I got the hang of using the software.
The download for Terragen can be found here:
The classic building guide on FormFactor, Alignments, and Color Palette section has been updated with more examples, along with how to turn off the improved QoL features for the Roblox Studio dragger. A preview of the Google Doc:
Sorry for late reply, new years stuff. This’ll be added.
This will be the last update for now. The author’s notes have been removed and clarified for better understanding. The following sections have been added: copying, references, and iteration. A new game has been uncopylocked as an example in the copying section.
Will you provide some example models for Terrian and rotated parts?
Unfortunately, not. There’s are many type of terrain in LEGO, but I mostly learned the building technique from Blockland (my most played game aside from Roblox).
For rotated part, this what you meant?
I just used Roblox Studio dragger with rotation (R) keybind (alignment section), used weld surface because of the functionality (surface types section), and needed to mimic that unidentified LEGO part.
EDIT: References section is updated for better understanding.
By rotated parts, I mean parts on hinges as shown in the post I’m replying to. Since I’m confused about what you mean by “adheres to hinge surface logic”
It would be nice to expand on hinge parts in the guide. 
It works like this, lol.
Classic Building Guide Update (1/7/25):
Classic Building Guide Update (1/8/25):
Very resourceful guide, I was going to look into this subject more, and when I logged on to find something about it, I ended up finding this. Thank you very much for creating and providing resources for the community to use!
