Revit light fixture family parametric ceiling offset

[Anonymous]

Hello, I'm trying to make a pendant light fixture family in Revit which can have a parametric length. I created a ceiling offset parameter but everytime I change the length, the size of the base alsochanges. How can I only change the length of the fixture without making changes to the base. 

Thank you in advance!

[martijn_pater · Accepted solution]

Add dimensions & lock those and/or add parameters to them. Also lock the geometry to your refplanes, else your pendant light falls off its cord...

Add dimensions & lock geometry to refplanes

[Anonymous]

Thank you! It worked!!