Posts from Dragon attack.
Справочник по НоММ-4 http://handbookhmm.ru/pamyatka-dlya-heroes-iv.html
Памятка по НоММ-3 http://handbookhmm.ru/pamyatka-dlya-homm-iii.html
и HotA http://handbookhmm.ru/vyishla-obnovlennaya-pamyatka-dlya-homm-iii-hota.html
To be honest, it's some kind of nonsense.
Let's assume we have a real situation:
Question: How should the green dragon attack to hit both the griffin and the pikeman at the same time?
In a different scenario:
The task is the same: the dragon must attack both the griffin and the pikeman without hitting its own units, but it must stand right next to the centaur.
Perhaps some will find these tasks absurd, and the answers obvious, but for me, for example, it's not entirely clear. That's why I created a diagram.
I think this topic is already in the physics engine, and it's explained there in a simpler way.

Although, according to the diagram, in these two examples, everything seems quite obvious.
you don't need to have ever seen the map layout, or even know about the existence of a physical attack, but it will hit 100% of the time.
I looked into it, and the problem is that the second cell of the ballista or tent is outside the battlefield, so even if the attack is supposed to hit it, it won't deal damage. If you attack by turning the head backward, this attack over two cells won't work – it will pass not through the side but through the top of the hex (at a right angle) and only hit the adjacent cell. These curved attacks are needed to deal more damage and take less in return, but they can't always be implemented.
Справочник по НоММ-4 http://handbookhmm.ru/pamyatka-dlya-heroes-iv.html
Памятка по НоММ-3 http://handbookhmm.ru/pamyatka-dlya-homm-iii.html
и HotA http://handbookhmm.ru/vyishla-obnovlennaya-pamyatka-dlya-homm-iii-hota.html
At the same time, the computer-controlled dragon manages to cast the ring in an empty space, let's say in front of the target, and thus damage it. Can a player cast the ring in an empty space as well?

I don't know, I immediately understood everything in the table; everything is clearly explained.
The dragon doesn't always burn in a straight line, as indicated by the sword (cursor). This happens when attacking two-cell units. When attacking, the dragon lands with its front part on the spot where the cursor points. If the dragon needs to turn around to attack, it lands with its tail on the spot where the cursor points. With two-cell units, it's slightly different. In the second case, the dragon doesn't turn around but chooses to attack the back part of the two-cell unit, and the burn goes shifted by one diagonal. However, if we were to the right of the target before the attack, during the movement, the animation turns the dragon around, and it lands with its head to the left, and attacks a different diagonal.
To put it simply, when attacking a two-cell unit, if we're flying from the left, the dragon attacks the tail, and if we're flying from the right, the dragon attacks the head.
Скажу я вам, мои друзья.
Я некромант, я маг великий, и армия моя
Непобедимая, огромная!
1st screenshot) The dragon flies in to attack from the left, and in this case, the skeletons will be burned!
2nd screenshot) Exactly the same situation, we also attack in the same direction, but the dragon flies in from the right side towards the target, and in this case, the devils will be burned!
Скажу я вам, мои друзья.
Я некромант, я маг великий, и армия моя
Непобедимая, огромная!