Hi, I'm Stephan Heuel

An agentic skill for interactive C4 architecture diagrams

stephan — Sun, 22 Feb 2026 00:00:00 +0100

We’ll be dealing with a lot more code in the near future. Using AI to help people understand existing systems seems more useful than generating even more of it. I built an agent skill that takes any folder of code and generates C4 diagrams and a local interactive HTML explorer for architecture review

New chapter: I'm starting as CTO & Co-Founder of Resilens

stephan — Thu, 19 Feb 2026 00:00:00 +0100

I am diving back into the world of sustainability tackling the pressing challenges of climate change. Together with a few long-time friends I co-founded a small company called Resilens

One year of Topoprint: Three new Ways to Improve your Prints

stephan — Sun, 04 Jan 2026 00:00:00 +0100

A year after launch, Topoprint has grown through community use and feedback across Switzerland. The post highlights three practical improvements aimed at making printed terrain models clearer and sturdier: route overlays, a stabilizing border ring, and multi-tile layouts. It introduces the new Designer Pro workflow for large prints, including examples and how to request print files.

The AI Emotional Loop

stephan — Fri, 28 Nov 2025 00:00:00 +0100

My perspective about AI swings between slot-machine chaos, mind-blown optimism, and Black Mirror dread. I turned that back-and-forth into an infographic about living in this emotional loop.

Fresh Features at Topoprint: RoundRects, Faster 3D Prints, and Improved Mobile Use

stephan — Tue, 02 Sep 2025 00:00:00 +0200

Topoprint now supports creating relief maps as RoundRects (rounded rectangles) alongside traditional disc shapes. Backend optimizations have accelerated 3D model processing significantly: a model that once took up to 10 minutes now completes in less than three minutes, complete with a progress bar update to keep users informed. Additionally, the Topodisc Designer web app has been revamped for mobile devices, making interaction more intuitive on the small screen.

Keeping the Lights On While Innovating: Finding the Right Agile Balance

stephan — Wed, 27 Aug 2025 00:00:00 +0200

Finding the right balance between Running-the-business (RTB) and Changing-the-business (CTB) can be challenging. This post explains that if RTB tasks are kept to a minimum, Scrum can be effective. However, if those tasks increase, adopting a hybrid or Kanban system can significantly help maintain smooth workflows and achieve operational excellence.

Multi-color 3D Prints with Topoprint

stephan — Thu, 26 Jun 2025 00:00:00 +0200

This blog post outlines the process of creating multi-color 3D prints using the Bambu Lab X1 Carbon printer and the Topoprint software. I explain how to prepare multiple STL files for distinct landscape features, using OrcaSlicer for effective slicing. The final print, requiring extensive filament changes, showcases the Landwasserviadukt.

Creative Connections: "Yes, yes, and..." Meets Rubber Duck Debugging

stephan — Wed, 25 Jun 2025 00:00:00 +0200

When someone proposes an idea to you, smile and assure them that you understand (yes ...). Express your enthusiasm about it (... yes ...) with an even bigger smile. Then, offer to enhance and extend their great idea (... and ...). You can compare this creativity technique to rubber duck debugging, but always remember that you should not replace a human with an LLM.

Seeing the Bigger Picture in Small Details: Birchgletscher’s Collapse

stephan — Tue, 03 Jun 2025 00:00:00 +0200

Last week, Switzerland’s Birchgletscher collapsed and caused a major rock avalanches, altering the landscape and burying the village of Blatten. With the data of the federal Rapid Mapping service and the help of individual experts, a first open post-event elevation model was made available. I used the model to create pre- and post-event visualizations and prints at a local scale.

⤴︎ Quick tip: Cloud backup with or without tech knowledge

stephan — Wed, 28 May 2025 00:00:00 +0200

If you're technically inclined, consider using Borg, Vorta, and rsync.net for encrypted remote backups. If that feels a bit too complex, Arq Backup might be a simpler option for you.

Updates from Topoprint: Designer, Bridges and Print-on-Demand

stephan — Mon, 26 May 2025 00:00:00 +0200

Topoprint has introduced three significant updates to its service for creating 3D mini-reliefs, or Topodiscs, of Swiss locations: bridges with arches, an easy-to-use Topodisc designer and an automated printing-as-a-service option.

Personal News: My First Day at Fotokite

stephan — Thu, 15 May 2025 00:00:00 +0200

Today marks my first day at Fotokite, a Zurich-based company that designs and manufactures actively tethered UAVs forpublic safety and emergency response. I’ll be leading the application engineering team and am excited to help build a great company with an innovative product.

⤴︎ Quick tip: Learn to love your inner demon

stephan — Wed, 26 Feb 2025 00:00:00 +0100

Demon Dialogues is a collection of comics which serves as a Handbook for Living with Your Inner Critic

One SQL statement to create a web map of Pizza places

stephan — Tue, 25 Feb 2025 00:00:00 +0100

The post explores an SQL query using DuckDB and OvertureMaps data to extract, filter, and visualize pizza places in Switzerland. All these steps can be done in one line, and the generated map of Swiss pizza places can be viewed immediately using PMTiles.

Swiss Rooftop Explorer - or how to serve a Low Cost Geo App with no maintenance

Stephan — Thu, 20 Feb 2025 00:00:00 +0100

The Swiss Rooftop Explorer is a cloud-native web app that retrieves Swiss building roof heights without a GIS server. Using PMTiles, Geoparquet, and DuckDB-WASM, it enables fast, low-maintenance geospatial queries. This post explores the data pipeline and its benefits of cloud-optimized formats, and how static files can replace traditional GIS infrastructure.

⤴︎ Quick tip: Tailscale for your gated community on the Internet

stephan — Mon, 17 Feb 2025 00:00:00 +0100

Use Tailscale to build your own gated community (a.k.a. VPN) within the public internet: bypass geo-blocking, remotely control your smart home, and quickly provide services as a developer.

⤴︎ Quick tip: Track and share expenses with Spliit

stephan — Tue, 11 Feb 2025 00:00:00 +0100

Use Spliit App (open-source, web-app, mobile app) for an easy way to track and split expenses with a group.

Thinking about AI and hallucination control

Stephan — Wed, 05 Feb 2025 00:00:00 +0100

The post discusses AI hallucination - when AI generates incorrect information. It explores two main problems: user frustration with incorrect outputs and uncertainty about managing these errors long-term. Using a geodetic network analogy, it explains how AI errors can propagate like measurement errors in surveying, suggesting we need better frameworks for detecting and managing hallucinations.

Creating architecture diagrams with C4 and AI

stephan — Sat, 18 Jan 2025 00:00:00 +0100

In this experiment I used AI to automate architecture documentation by testing Aider (an AI coding assistant). After just 5 minutes and 5 prompts, I generated a decent C4 diagram for a Streamlit web application. While not perfect, this experiment shows the promising future of AI-assisted documentation.

Playground: A book about climate crisis and AI

stephan — Tue, 14 Jan 2025 00:00:00 +0100

"Playground" by Richard Powers explores the interplay of technological ambition and environmental concerns, highlighting tensions between progress and preservation through diverse characters on a remote island.

How I do research on the web in 2025

stephan — Sat, 11 Jan 2025 00:00:00 +0100

In 2025, research on the web involves using ChatGPT for specific technical queries while considering sources and environmental impact, as Google's search has become less efficient.

How I automatically publish my web favorites (minimal AI included)

stephan — Thu, 09 Jan 2025 00:00:00 +0100

This article describes "star-collector," a tool for automatically publishing web favorites using GitHub Actions and AI-generated titles, leveraging transformers for title creation from Mastodon posts.

Topoprint.ch: Turn Any Swiss Location into a 3D-Printable Model

stephan — Sat, 04 Jan 2025 00:00:00 +0100

Introducing Topoprint.ch, a platform for creating personalized, 3D-printable topographic models of any location in Switzerland, accessible through social media bots. This post explains the "what," the "why," and a bit of the "how.".