If you want, I can:

In the world of Computer-Aided Design (CAD), particularly within the Autodesk ecosystem, automation is king. For decades, power users and developers have relied on Visual LISP (VLISP) to streamline repetitive tasks, automate complex drawings, and build custom tools for AutoCAD.

Today, security by obscurity is no longer the goal. Autodesk has pushed developers toward .NET (C#/VB) and JavaScript APIs, where decompilation is trivial (tools like dotPeek or ILSpy). Ironically, modern .NET plugins are easier to reverse engineer than the old VLX format.

There is no "official" or perfect decompiler for VLX files. Most tools available are third-party, community-driven projects that vary in effectiveness and reliability.

It is crucial to address the intent of use.

If you are looking to decompile files related to Velux smart home devices (often embedded systems), this is hardware reverse engineering.

Before understanding a decompiler, one must understand the target. A VLX file (Visual LISP eXecutable) is a compiled, binary format generated by Autodesk’s Visual LISP compiler.

The primary function is extracting LISP source code.

For example:

Uncompiled, human-readable ASCII text files containing standard code structure. These files can be natively opened, audited, and modified inside any standard text editor or the Visual LISP IDE .

A single AutoLISP file compiled into a binary format. Compilation syntax removes comments and reformats the structure into machine-readable bytecode to increase loading speeds and offer a basic layer of code protection.

Finding a modern, functional VLX decompiler is difficult. The golden age of these tools (circa 2005–2015) has faded. Most existing tools are command-line utilities shared on obscure Russian or Chinese CAD forums.

: Open the decompiler application, click "Open" or "Select File," and choose your LISP-based Decompilers : Load the decompiler routine into AutoCAD using the

As a general rule, decompiling software you own the copyright to (for recovery purposes) is legally permissible in most jurisdictions. Conversely, decompiling commercial third-party plugins to redistribute them or steal proprietary algorithms is a severe violation of copyright law. If you are trying to recover lost code, let me know: Do you have any or .fas components?