can i play pure str character?

i have just finished gothic3 with mage character
and i think about start new game with str character
can i play throughout the game by using learning point in str and hit point and using sword
will i survive boar 's stun lock
will i survive a horde of orcs in vangard or in nordmar camps

You will survive if you're strong enough + with a lot of save and load. It's really difficult in the Nordmar camps when you don't have any ranged combat (magic, bow or xbow), but it is possible.

It should work just fine. You will want enough thieving skill to pick difficult locks and enough hunting to capture trophies (30 points IIRC), but you can put the rest into weapons and resistances.

A spear (doesnt require any two handed skill) or a halberd will see off the stun-locking animals. Enemy casters can be dealt with using melee and a summoning or ice lance scrolls (save scrolls for when you are up to many casters simultaneously).

The only enemies that I have difficulty with in melee are the ogres, who are hard to stun and have quite the reach and punch. They are best dealt with using a bow which will take quite some time if you only have 30 points of hunting. Trolls can OTOH be dealt with using spear or halberd once isolated from the group once your fighter is strong enough. At any rate I think most trolls and ogres are avoidable. There are also a few dragons that best are taken out with bow, but they are rather out of the way.

You shouldnt have to put any points into alchemy or ancient knowledge, but once you have the prerequisites you might want to learn heal other (useful for healing companions), making perma stat potions, ice lance from a druid/water mage (freezes enemies, VERY useful when fighting multiple casters) and bloodlust from a beliar shrine (can be used to take out peaceful casters in an exploity way, make a guard attack the mage, stun the guard so that the mage can kill the guard, and watch how the other guards slaughter the mage screaming "murderer!"). Of those I'd say that the perma potion is a no-brainer (making two strength or hunting potions is enough to recoup the cost) and ice lance extremely handy, while the others are optional. You should get the prerequisite AK and alchemy from stone tablets and books.

And I find crossbow pretty useless. You'll usually only get off one shot before the enemy gets close. I wouldnt spend any points on learning that shitty weapon.

EDIT: I'd also spend LPs on sharpen weapon and prospecting (doubles the yield from mining). You might want to get to "forge ore weapons" for the sake of a quest in Nordmar, but apart from that the cost benefit analysis doesnt speak for spending points on smithing. You can get some smithing points from quests, but probably not enough to learn forge ore weapons. Leave 10-15 late game LP unspent in case you decide to go for this skill when in Nordmar…

I've done it, shouldn't be too much of a problem. Keep a few things in mind:
- Pump up loads of strength so you can use the orc halberd. Best weapon in the game, by far (crazy range, very high damage).
- Put whatever points you have left into hitpoints: 500+ is recommended.
- Help the orcs so you get the "Health Regeneration" skill, this will help out a lot.

After you get those three, the rest of the game is easy.

You can play a str character. There are some critical points. Even the first village Ardea has a shrine. Use shrines to increase your HP. For instance in the mid of the game at level 40 I had 1000 HP. You should have both one hand and two hand weapon skill. Because you should use spears/halberds or orc weapons against beasts. And against people and orcs you will use one hand sword. Shield is not necessary. In Mrytana, you can learn level 3 one hand weapon and level 2 two hand weapon. In northlands you can learn level 3 two hand weapon. You can prefer to learn dual wielding in the desert. The third criteria is strength. Both for defence and offence. At level 40 I had 300 strength and beasts can not make you fall down easily with this high strenth. And you can use good two handed orc weapons against beasts. Do not spend skill points for bows or hunting. Maybe you can use supporting skills as resistances, armor and paladin skills.

To summarize, to make a str character, use your skill points at
1. one hand and two hand weapons
2. strength
3. hit points
4. resistances, armor and paladin skills

The first level of shield is rather nice to have. When fighting with 1H weapons an equipped shield can give rather significant armour bonuses even if you dont use it for active blocking.

I wouldnt bother with the highest level of 1H and 2H skills, since the knockdown effect you get from mastery actually makes it harder to kill enemies, and you dont really need them for access to weapons (having a long blade is usually more valuable than a few extra points of damage). Many of the high damage weapons suck for range and are thus fairly useless, like the 2H axes and the rune sword. A bastard or paladin sword coupled with a halberd (or even a spear which you dont need any 2H skill for) will see you through the game.