First of all create a reference plane in desired position and if you like lock it to the roof plane this way if you raise the roof the purlins etc.
Revit roof reference plane.
Open the 3d view and click architecture tab work plane panel set.
To pick an existing line.
Detailed review of reference planes beam and roof systems.
Use the line tool or the pick line tool to draw a reference plane.
On the draw panel click pick lines.
To align roof ridges use the align tool.
Alternatively they can actually be used to control the formation and position of 3d geometry.
Revit places a reference plane at the specified offset.
Will go with it.
Move the cursor near the line to which you want to place the reference plane and click.
In the drawing area draw the reference planes by dragging the cursor.
Select the reference plane and on the properties palette enter a name for the plane.
Another un cut version of bim building information modeling.
Now the trick is select and name the ref.
Click modify to end the line.
Simply they can be used to form a draft outline of where you need to position certain elements.
Using the reference plane you can control the position of the extruded roof in relation to a level.
Click finish edit mode and then open a 3d view.
Reference plane properties select a reference plane and view or modify its properties on the properties palette.
On the options bar specify an offset if desired.
To raise or lower the roof from the reference level specify a value for offset.
Hide the reference plane in the view hide a selected reference plane or all reference planes in a view.
Name reference planes name each reference plane so you can assign it to be the current work plane.
Select the lock option to lock the reference plane to the line.
Sketch the profile of the roof as an open loop.
Used in this way they are acting as simple construction lines.
In revit reference planes can be used for two main purposes.
Using the reference plane you can control the position of the extruded roof in relation to a level.
Sketch the profile of the roof as an open loop.
In the work plane dialog select the reference plane name you just created and click ok.
Plane if you don t none of this works.