How to show the Centreline Tick Mark in dimension for Grid Lines
It is extremely frustrating that it is impossible to differentiate the tick mark for the grid line. The grid head doesn’t have the reference plane to snap or similar. It will always require something to snap to show the centreline. There are a few workarounds to resolve this issue such as using Detail items or invisible 3d model.
What you need?
To enable the different tick mark, you need the reference plane with Center defined. Snapping the reference plane will show the tick mark you want.
Workaround 1 - Detail Items
Using the Detail Items could be a solution to this. However, as it is a symbol, it has to be view-specific, which means you need to place it to all views that require the set out. Moreover, it needs to be grouped to place to the identical layouts. As a result of that, the file size will be slightly increased and might impact the model performance if it is a complicated project.
Workaround 2 – Generic Model
Using the generic model could also be a solution to this. However, as it is a 3d object, there should be extra works to be done.
Firstly, it shouldn’t show any lines or models, it should be a reference only. Secondly, it should have the option to control the base and top levels so that it doesn’t need to be copied to other levels or be grouped. To achieve this, the family template should be the two levels generic model or similar.
Moreover, in order to display the invisible references, there should be 3d invisible lines on plan and elevation so that it can be cut. The 3d object doesn’t work as it will be displayed in 3d views.
Set the base level and top level to show in all levels, then you don’t need to group them at all. Furthermore, assigning them to the primary design option would be beneficial as it will only appear when snapping the object.
To Sum Up
The grid should be recognised as Centreline since it should show the clear indication of the set-out in dimension. It is very common in documentation to represent different graphics of tick mark to communicate whether the set-out is from the face, edge, grid, etc. Hopefully, Autodesk will include this feature in the future.