Getting Started
This chapter helps you build your first correct DAQS rule and understand how Revit data flows through filters and validations.
The goal is not speed — it is accuracy. Once your mental model is right, everything else becomes easier.
What you will learn
By the end of this chapter, you will be able to:
- Recognise and understand JSONata syntax symbols
- Read and understand the DAQS JSON export structure
- Write your first JSONata filter
- Understand why filter output shape determines validation logic
- Avoid the most common beginner mistakes
- Use a minimal test dataset to practice filter expressions
How this chapter is structured
JSONata Syntax at a Glance
Before reading a rule, you need to recognise the symbols.
This page explains every symbol you will encounter — $, ., [ ], { }, ( ), and more — with short examples you can try immediately in try.jsonata.org.
First Rule Explained
A step-by-step walkthrough of a complete, minimal DAQS rule. Explains what each part does and why it exists.
Minimal Test Model
Why you should never start with a full production model — and how to build a small one that proves your logic without noise.
Small Dataset (JSON)
A ready-to-use JSON snippet you can paste into the JSONata Exerciser. Use this to practice filter expressions while reading this chapter.
Common First Mistakes
Patterns that look right but break silently:
- Filtering at the wrong object level (instance vs type)
- Assuming parameters exist when they may not
- Mixing type and instance logic in one filter
Prerequisites
You do not need:
- JSONata knowledge (this chapter starts from zero)
- Revit API experience
- Programming background
You do need:
- Basic understanding of Revit Families, Types, and Instances
- The JSONata Exerciser open: try.jsonata.org
Important mindset
Filters select data. Validations judge data.
If your filter is wrong, your validation will always be wrong — no matter how correct the validation logic looks.
This chapter focuses on getting the filter right first.
Where to go next
Once you complete this chapter, continue with:
- Core Concepts — understand the Revit data model before writing more complex filters
- Filters — learn how to scope rules precisely and safely