How do you think, what would be best to do if user avatar hits a wall? You can't just stop hand image at the wall or it will break immersion (for Touch control). And you can't allow for it to go inside (or it could turn on some button behind the closed door).
I have an idea to make avatar ghost like if it hits some wall or other object. So it will be semi-transparent and can't control any game object. Another idea is to stop the game until user get his hand out of wall 🙂 That will not be very nice to user, but he will avoid hitting the wall next time. Up until he actually feels that wall in his imagination. 😉
Is there any other way to do? Will this idea works?
ghosting your hand if you move it through a wall... that's not a bad idea. Of course, you won't see your hand if it is entirely through the wall though, but it could ghost out as it starts to enter. Could apply to your arm too. Alternatively, stopping your avatar arm as it hits an object while your physical arm is still moving (and then having to realign them afterwards) would break any continuity.
A related problem occurs with the DK2 when you lean your head through a wall. There is at least one demo where your view would gray out if you tried that. I thought it worked pretty well and MUCH better than the game letting you stick your head through and seeing what was on the other side. Even worse is the jarring effect of stopping your view from moving like when you lose head tracking.