# Exclude from Gravity Point Calculations

To insert the Gravity Point or to calculate the mass of an Assembly, all solids in the Assembly must have a material with an assigned density parameter.

By using **Exclude from GP** parameter, you can make an exception to that.

![](https://239424168-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqtUsszuAWXIZhQhrvjnb%2Fuploads%2FZEMk11vg9l9VELyedX7H%2F0.jpeg?alt=media)

All elements that have this parameter turned ON will not be included when calculating the Assembly mass or the center of gravity.

In this example, the grout tube for a precast wall has this parameter active, so the Assembly Mass and Element Mass parameters are empty:

![](https://239424168-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqtUsszuAWXIZhQhrvjnb%2Fuploads%2FmN47VhJrc52Otz8b5w37%2F1.jpeg?alt=media)

Other families, however, were included in the calculation of the Assembly Mass and the center of gravity.

![](https://239424168-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqtUsszuAWXIZhQhrvjnb%2Fuploads%2FWmxutUF7VmcwlN1rYZ8D%2F2.jpeg?alt=media)