Why am I unable to adjust relative base height on a spot grade?

[svalente9GJKH]

My relative base height option is greyed out/not able to be edited when I click on a spot grade.

Why might this be?

Thank you

[ToanDN]

A spot grade?  Do you mean a spot elevation or a spot coordinate?

[barthbradley]

Create a TYPE that uses Relative Elevation Base. Then that one will give you the Option to pick Ref. Level.