So I got into making resized avatars...

[DerpWolf]

https://gyazo.com/8b595226fddb320865afe4d8566b4c17

... and the problem emerged. Taking a seat causes it to bury into the ground:

https://gyazo.com/13b87f8fda0e3f158c6cc54840ac2d50

Yeah this is common problem, but asking anyway, maybe the solution is found over the years. I can detect when the avatar is sitting from script, but not much more. Neither edit its Z-position directly or somehow use llSitTarget to tweak it (since latter requires sitting on specific prim). 

[Ruthven Ravenhurst]

I think this is more of an animation problem. I assume you're using custom animations or an AO? The animation itself or a sit target (or maybe hover height?) would need to be raised up from the normal center point

[DerpWolf]

Hovering height is set so avatar stands on ground firmly. I cant set hover height for sitting separately. Thats why I looked for scripted solution. Since sitting action can be detected by script, and make script to do stuff according to it. The question is what to make it to do. So far I havent found the way to script z offset.

And no, I'm not using animation overrider here. Just  resizer with custom joint positions.Maybe a good idea though. If we can add custom sitting animations, I can raise avatar root position that way. I'll look into it as well.