Masking region in family won't appear in some instances

[Redrunner92]

I'm making a thickened footing family and I have a masking region applied for the plan view. The masking region's purpose is to show the outline of the bottom face rather than the top face. Before I apply the masking region the family shows up as expected; after I apply it, some instances disappear entirely. I want the modeled element's lines to disappear, in the family editor I have set those to not show in plan view. But the masking region's lines don't show in the project either even when I have certainly drawn it; what is causing this? Indeed, some instances have the masking region's outline showing but others do not. I have provided the family here and an image of what happens after I load the family with the masking region. In the image, the red arrows are showing that I have an instance selected but no lines are visible, not even the masking region's; the blue arrows are pointing to a row of instances where the masking region's lines are visible.

[barthbradley]

Does it display differently if you change the Category from Structural Foundation to Generic Model cause? 

Also, is the Masking Region Drawn in Foreground? 

[barthbradley]

Sorry; I hadn't noticed that you posted rfa. Can you post your rvt? I can't replicate.  

...is the one not shown within the View Range?  

[Redrunner92]

Yes and yes, but that is not my concern here. I will change the category if necessary but I'm perplexed as to why the Structural Foundations category is causing this issue.

[barthbradley]

I'm seeing a "-4" offset. What is the View Range?

[Redrunner92]

Here is the .rvt file. Yes the object is within the view range, I don't see how it couldn't be with a -20 foot bottom and a +20 foot top. The -4 inch offset is to put the elements on the bottom face of the 4-inch slab.

[barthbradley]

Use the old model line trick. 

...in Family, draw a model line in Elevation extending upwards a little bit from the Ref. Level.  

[Redrunner92]

That isn't working, unless the model line must be taller than 8 feet (the highest I drew it).

And as for workarounds, I thought of that too. I'll make this a Generic Model if need be. My question here is why is this behavior happening?

[barthbradley]

Very weird, buddy. No clue what's going on.  Can't even switch it's Category.   But, if you get rid of Masking Region and just use Symbolic Lines, it seems to correct display. 

[Redrunner92]

They work until two of the footings meet in a T shape or L shape. Then I would need to choose if I want the symbolic lines to butt up to each other or if I want the lines to intersect, of which neither is an accurate representation.

I appreciate your looking into this. Your expertise is quite helpful.

[barthbradley]

If you want a Masking Region to be able to overlap and obscure another instance of the Family in the Project, you would need to uncheck "Draw in Foreground" and host Masking Region to a named Ref. Plane. Then label this RP to an Instance Parameter to control it's height in the Project so you could actually OVERLAP another Instance of this Masking Region Family.  

more fun-filled facts from AKN: 

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/CloudHelp/cloudhelp/2016/EN...