It exists but not in my visual field, so not in front of me. I can imagine it in my visual field but that is distinct from it actually being there, which may not make much sense unless you do the same.
Not sure if it's a useful data point, but my ability to construct things in my head improved dramatically after I'd been messing around with CAD for a few months.
My guess is it just got my brain to improve it's ability with that stuff, and the side effects helped in other areas (like this) too. :)
If I say: "imagine a red triangle", can you do it easily? Is it red? Does it visually exist in front of you?
I have asked many people this, and many people say it is laughably easy. This tells me it is "normal".
I can't do this. I also have a terrible episodic memory. But my semantic memory is fantastic.