I'm trying to create a depth of field system using a primitive line attached to a null that I would move where I want my focus to be int he world space.

I have a line primitive and I appended a measure sop to get the perimeter… I've created a null and added an empty parameter called perimeter. I need to pass the perimeter value to this new parameter in the null so I can reference it in a the camera focus distance.

The measure will generate a primitive attribute called “perimeter”, so you're going to need to use the “prim” expression to access it from your null's parameter. So something like:

prim(“../measure1”, 0, “perimeter”, 0)

… where the first zero represents the primitive number you want to check (0 is correct if your line is only one primitive) and the second zero is the index of the attribute - perimeter has only one index, so again 0 is correct here.

Hope that helps.

THANK YOU!

That worked perfectly!!