# Query Material Data

> High-fidelity material extraction skill for Revit Snapshots. Resolves physical material names (e.g., "Steel, Carbon") by joining ElementId references to the Material category, bypassing unreliable text parameters. Use when this capability is needed.

- Skill: `tomevault-io/query-material-data` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/query-material-data`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/query-material-data/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/query-material-data

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# Skill: Robust Material Resolution

This skill provides a standardized method for resolving physical material names from Revit snapshots. It addresses the common issue where text-based "Material" parameters are empty, inconsistent, or hold internal Type names instead of physical material identities.

## 1. Core Logic & Assumptions

### ElementId Referencing
In Revit, the `Material` parameter typically stores the **ElementId** of a Material element, not a string. This skill assumes that the true material name is stored in the `Name` parameter of the associated Material element.

### Join Hierarchy
1.  Identify the parameter ID for "Material" on the host element.
2.  Extract the `value_int` (ElementId) from that parameter.
3.  Join this ID to the `elements_global` table to find the Material element.
4.  Join the `Name` parameter ID from the `parameter_catalog_global` to extract the final string.

## 2. Standard SQL Template (Global Scoped)

```sql
SELECT 
    e.document_id,
    e.element_id,
    mat_name.value_string as ResolvedMaterial
FROM elements_global e
-- 1. Get the Material ElementId from the host
JOIN element_parameters_global ep_ref ON e.document_id = ep_ref.document_id AND e.element_id = ep_ref.element_id 
    AND ep_ref.parameter_id = (SELECT parameter_id FROM parameter_catalog_global WHERE parameter_name = 'Material' LIMIT 1)
-- 2. Join to the Material Element's 'Name' parameter
JOIN element_parameters_global mat_name ON ep_ref.document_id = mat_name.document_id AND ep_ref.value_int = mat_name.element_id
    AND mat_name.parameter_id = (SELECT parameter_id FROM parameter_catalog_global WHERE parameter_name = 'Name' LIMIT 1)
WHERE e.category_name = '{CATEGORY_NAME}'
LIMIT 100
```

## 3. Best Practices for Developers
- **Token Efficiency**: Material joins can be expensive. Always use `DISTINCT` or `GROUP BY` when performing takeoffs to minimize the result size.
- **Parameter Lookup**: Use `(SELECT parameter_id FROM parameter_catalog_global WHERE parameter_name = '...' LIMIT 1)` instead of hardcoded negative IDs to ensure compatibility across different snapshot versions.
- **Scoping**: Always include `document_id` in joins to prevent cross-model data contamination.

## 4. When to use this skill
- When "Pipe Material" or "Wall Material" parameters return empty strings or numeric IDs.
- For specialized takeoffs where the exact physical substance (e.g., "Concrete - Cast-in-Place Gray") is required.

## 5. When NOT to use this skill
- When the `type_name` or `family_name` is sufficient for the user's request.
- When querying non-physical elements (e.g., Views, Sheets, Schedules).

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<!-- tomevault:4.0:skill_md:2026-04-11 -->