There are some spatial intelligence tests that essentially require mentally rotating and flipping 3D objects in your mind's eye. That could maybe be one way. Can't speak to the quality of this test, but here's one that might apply: https://www.psychologytoday.com/us/tests/iq/visual-spatial-i...
I don't think this tests aphantasia at all really. I have a very weak mind's eye and I've always been able to score very highly on visual spatial recognition tests. I can still conceptualize and rotate items even if I can't picture them clearly.
Interesting. I always "perform" the rotation in my mind's eye, so I guess I figured that's how most others did, too. Typical mind fallacy strikes again.
According to https://news.ycombinator.com/item?id=29087803 I have aphantasia, but I no trouble mentally rotating and flipping 3D objects - but I'm not rotating a image of the object, but more like concepts.
I did it correctly enough apparently ("Your score on the test was the top of the charts") but I didn't have to visualise anything (it's very difficult for me to visualise anything more than fleeting glimpses of vague shapes).
The answers are easy enough to find without having to perform any imaginary rotation but just eliminating candidates one by one by looking at which features would match or not.
That's not a free test and you are informed of that only after you pass. That's too predatory for me that I don't really care how accurate their tests are.