RIP
CyberGene navindra the fatigue with acoustic pianos is physical, it comes from a sound that overwhelms in sheer volume and you can’t turn it down. The Pianoteq fatigue is mental and is not related to any physical discomfort. I’d describe it best as boredom and sameness for the mind. When I’m fatigued by a real piano I need to rest. When I’m fatigued by Pianoteq I need to switch to a sampled piano and it’s a relief. Those are two very different types of fatigue.
That is very interesting. I've not used either sampled or modeled instruments for long enough period of times (since I've always played them only as "back up" for the acoustic being used by another family member, or by need to use low volumes not to disturb another family member). So I cannot give you my "authoritative" experience, but in my small thing, I've experienced the "sameness" with anything: from the internal sound of digital pianos (worse offender especially the old ones), to all the virtual instruments I tried, without exception so far. In my case, the "fatigue" results in any digital piano sound feeling "unacceptably bad", not being able to distinguish one piano sound from another and having to stop practicing (but could keep playing "for fun" if I am in the mood). When I could switch to the acoustic right at this point, I always surprised to learn that it sounded "perfect" (even when it was the old, too-bright upright). I'm looking forward to having Mybrid completed and try more to see what happens with more regular sessions!
It's also interesting to note that some players, have the same complain you have with PTQ (sounding boredom with sameness of sound) for the sampled instruments, and they find relief in PTQ which they claim sound "different" even when played "almost but not exactly" the same. Most vocal with this claim is obviously Phil Best.