---
title: "Get the mass properties for the assembly."
method: GET
path: "/assemblies/d/{did}/{wvm}/{wvmid}/e/{eid}/massproperties"
tags: ["Assembly"]
---

# Get the mass properties for the assembly.

`GET /assemblies/d/{did}/{wvm}/{wvmid}/e/{eid}/massproperties`

## Request

- Base URL: `https://api.onshape.com/api/v17`
- URL: `https://api.onshape.com/api/v17/assemblies/d/{did}/{wvm}/{wvmid}/e/{eid}/massproperties`
- Auth: OAuth 2 and HTTP basic
  - Authorization code: `/oauth/authorize`
  - Token URL: `/oauth/token` scopes: `OAuth2Read`

The assembly must contain parts that have density. The returned schema includes the same information as in the Onshape [Mass Properties Tool](https://cad.onshape.com/help/Content/massprops-asmb.htm). 
When three values are returned: 
 * The first is the calculated value. 
 * The second is the minimum possible value, considering tolerance. 
 * The third is the maximum possible value, considering tolerance.

## Path parameters

- `did` string, required
- `wvm` 'w' | 'v' | 'm', required
- `wvmid` string, required
- `eid` string, required

## Query parameters

- `linkDocumentId` string
- `configuration` string
- `namedPositionId` string

## Response `default`

default response

## Changes

- **2026-09-19** `c16acb88e3ea`: 1 info
  - added the new optional `query` request parameter `namedPositionId`

[Operation history](https://skmtc.dev/onshape/apis/onshape-rest-api/changes/assemblies/d/:did/:wvm/:wvmid/e/:eid/massproperties/get.md)

---

[API](https://skmtc.dev/onshape/apis/onshape-rest-api.md) - [All operations](https://skmtc.dev/onshape/apis/onshape-rest-api/llms.txt) - [OpenAPI document](https://skmtc.dev/onshape/apis/onshape-rest-api/revisions/c5c4c780f831?raw)