Shape Handler how to edit by specific Dimension

[chen1588]

Hi guys as I am a pretty new user in Revit, I could not find any methods to change the dimension of the 3d rod using shape handler. Unfortunately, the file that I am trying to edit cannot be shared. The file was sent over to me and there were some missing entities hence I am required to edit few parts within the model. 

I am unable to understand why some shape handler for part of the rod could move the dimension down at a scale of 0.1mm while this specific part of the same rod could only shape handler at a scale of 1mm. Currently the part is at 8mm and I require the protruding part to be 7.5mm.  

[vitorbortoncello]

você precisa editar a família e criar parâmetros de instância usando dimensões. Eu tenho um cubo que fiz por exemplo, usei o parâmetro Height para controlar a dimensão

[chen1588]

Unfortunately when editing the family, the rod is a full length version, but as shown in the picture below, there are gaps in between. The project was passed over to me and I was not the one who drew everything there. Is there anyway I could edit other than the method above or if you could kindly give me steps on how to resolve it? Thankss