Finding the Workshop
In the beginning of the summer of 2015, spurred on by having just completed the newly-released Portal Stories: Mel, and wanting more maps to play, I discovered the PeTI level editor and the online workshop of other people's maps. I played a huge number of them over the next several months, including most of the famous sets (Sendificate, 12 Angry Tests, and more), and slowly became familiar with many of the common "tricks" employed by custom maps.Trying It Myself
At the end of that October, I finally took the plunge and decided to try making my own, creating what I still consider a halfway decent puzzle. At that point, I was hooked, and pumped out 17 more chambers, including a couple I still consider fairly good and fondly recollect (and just as many fairly poor ones).
Recursion in development.
Returning With BEEMod
I moved on to other activities for the rest of 2015, and all of 2016, but returned to making maps in the beginning of 2017, and this time with something new: BEEMod. I was not about to do what some people do and make chambers packed with unusual test elements for the sake of it, but it allowed for far more customized styling (geometry, theme, music, and more), logic elements to simplify complex systems, hidden triggers, and useful utilities like signage and cube coloring. Some custom elements did make their way into my chambers, notably the PS:Mel death fizzler, which I continue to use extensively today.Looking Deeper
The following summer, I was working on a gimmick/exploit abuse map (ie a map that is solved by doing things that are normally exploits or at least very unintended mechanics). The map took some inspiration from (and is named after) the Portal-themed "You Monster" expansion pack to the tower defence game Defence Grid, where a late-game level there involves similar abuse of mechanics to bypass an otherwise unwinnable situation. Because of how perfectly they would fit, I decided that I would like to use Glados' voice lines from that map, and so ended up picking apart the BEEMod package system to insert those sound files as new choosable chamber start and end lines.Trying Out Hammer
From that point until May of 2019, I continued to just use BEEMod as it came, but after putting out over 40 chambers, of varying quality and design, since I had started using it, I decided to try something slightly new. Using my package reverse-engineering knowledge from the previous year, I decided to pick apart the 60s flamethrower item and turn it into a simple fire pit, allowing me to have what was functionally no different than a goo pit, but with a much more dramatic and unique appearance.Hammer Part II
Returning to mapping in 2020 (and at this point noticing a pattern of how I tended to do it between roughly April and August every year), I revisited using Hammer to create custom items, but went far beyond a single item. It started with a simple "nonportalable white wall" to fix an exploit in Organized Chaos without ruining the aesthetic (which never even got used for it, but did find extensive use in later maps).
Once I finished that I decided that it was time to revisit a long-standing dream of mine, to have colored and/or dynamic lights to enhance the visuals with things like lasers and reversible funnels.
Once I got that working, I revisited an old map idea using such funnels from the previous year, expanding it into what would become Blue And Orange. In the process, I ended up making several other Hammer items, some aesthetic (partial walls, sound triggers, et cetera), some technical (eg walls with specific grating formations to allow bridges and not funnels, hidden controls to destroy all cubes with a "reset" button, and so on).
That exploded in scale with the next map, Natural Light. For that chamber's "overgrown and destroyed" aesthetic, I ended up creating several large setpieces.
The first of many.
As that map developed, I ended up creating a plethora of different items to aid the solution, such as sparking electrical wires - which end up being effectively a grating that is later removed - and a bunch of debris specifically designed to block unintended portal placement or laser aiming.
Rarely did things work well on the first attempt.
The control room setpiece designed to turn off those wires, along with being an excuse for yet more dynamic lighting.
This practice continued throughout the rest of the summer, culminating in the giant open pit for Redshift, finally enabling me to attempt my favorite puzzle style - Wheatley-style destroyed chambers with huge holes giving view of the enrichment center outside (and equally huge open spaces), as well as dynamic elements.
This continued again in 2021 when I - once again in the spring and summer months - returned to making maps. This time, I went even further, making large highly-dynamic setpieces, such as the chamber redesign "cutscene" in Anticipation.
At this point, I have a huge library of custom items, and fully expect more to come, continuing to enrich future chambers.