AI + GDL

[Patrick M]

I spent way too much time trying to teach chatbots, like chatgpt and gemini, the gdl help manuals/cookbook/etc... every script they threw at me was total garbage.
It turns out the 'full version' of claude is actually really useful for generating scripts, and even includes help guides for setting up parameter lists and trouble shooting bad script!

I threw a complex light fixutre together with a cut sheet, manuf. image, and a basic parameter:
"I need a light fixture from the attached cut sheet and image. It needs hotspots for each arm's angle and length. It needs a parameter for pendant length from the ceiling and a hotspot at the mounting point. max polygon count should be 15,000"

I didn't even need to request a 2d symbol, but I have no doubt it would edit the symbol to be whatever I need it to be given a few revised prompts.

I definitely recommend claude for GDL assistance!

object attached, for anyone curious.

Operating system used: Mac Apple Silicon

[Miles Smith]

Personally, I really like your file naming convention for this.

[Patrick M]

a bit tongue in cheek... as this took almost 0 GDL skills at all (it helped to know the terminology, like: paramater, value, array...)

[Patrick M]

it is the desktop app, but I've been told the browser interface may have some advantages. Opus 5.5 medium

[Laszlo Nagy]

Thanks. That is pretty good if a non-top-of-the-line model with Middle effort can create such useful GDL library parts. I will need to test it myself. The future looks bright for custom content creation in Archicad.

[Ricardo Heim]

Just adding up to the conversation, I'm now starting to mess with the LLM to code some GDL also and I found useful to creata a config file where you give the AI the context of who you are, what are you trying to accomplish and a set o skills to guide it to do all the things needed for a GDL script using less tokens. I'm using the deepseek 4.1 flash API with the deepseek harness as it is most cost effective here in Brazil and I'm getting good results. I told the AI to do all the configuration, creating the config file, the skills...

[Keny90]

AI has advanced tremendously in recent months. I use the Claude desktop application—specifically the "Claude Code" window—running the Opus 5 (now version 5.5) model at the "High" setting. It is connected to Archicad via an MCP connector, allowing it to code in GDL with incredible efficiency. As a side note, it’s brilliant not just at GDL but also at model checking and construction—though GDL is the focus here.
Up until now, I’ve mostly given it existing elements that needed modification or repair. I simply copy the relevant .gsm file over, tell it what I want, and it handles the rest: converting it to .xml, doing the work, converting it back to .gsm, and then notifying me to refresh the library. I don’t have to copy and paste code manually.
I’ve been writing GDL objects for over 20 years; while I’m not a professional developer, I can certainly hold my own. There were a few objects I had abandoned in the past because I’d reached the limits of my expertise. I set the AI ​​to work on some of these elements, and it successfully finished and fixed them. Honestly, I was blown away by how flawlessly it codes. Here are a few examples of what it has done:
I needed a piece of furniture quickly, so I assembled it from slabs and saved it; later, I gave it to the AI ​​to turn into a parametric version. I converted an office chair from Rhino; the result was an ugly object with a massive polygon count and visible edges. In this case, too, it worked with the .gsm file, as the original .obj or .3ds files were no longer available. It optimized the polygon count and removed unnecessary edges.
What really amazed me was when I gave it a standard single-leaf door from the basic ArchiCAD library and asked it to make one of the divided door panels parametric—allowing the height and thickness of the divider to be adjusted. For those unfamiliar with the subject: I consider doors and windows to be among the most complex elements, involving over a thousand parameters and nested macros. To my great surprise, it only messed up a minor detail in the user interface; apart from that, it executed the task flawlessly.
The next step is to have it create a completely new element with complex functionality based on a written description.

[claudiuiancic]

I created a Claude Code skill and have achieved surprisingly good results so far. You might want to test or use it yourselves. You can find it here:
https://github.com/claudiuiancic/gdl-skill