Hi! I am new on this field.
Currently I am using 3d gamestudio 7 pro version.
The questions are:
1. Is it possible the 16:9 (1600x900) screen resolution?
2. And - if yes - how can I do it?
Sorry for my English.

vec_set(screen_size,vector(1600,900,0));

What it means - sorry?
As I understand, 'vec_set' is a set of vectors.
To be more concrete: what I have to do to change default screen resolutions (4:3) in the 'techdemo_A6'?

its set screen_size parameter to 1600x900
also you can set it by x and y parameter

http://www.conitec.net/beta/ascreen_size.htm

and you can check video_mode function

http://www.conitec.net/beta/avideo_mode.htm


PS- techdemo_a6 used C-Script, its very old programming language.
some information about how convert C-Script code to Lite-C

http://www.coniserver.net/coni_user....html?information_for_the_a5_engine_.htm

http://www.conitec.net/beta/litec_migration.htm


If you are just starting to work with 3DGS, then I highly recommend studying only Lite-C

Of course, all these parameters need to be changed in the main script of the project, probably in the function Main()

советую тебе в целом изучать мануал и AUM (там очень много хороших примеров)
и вообще подумать с какой целью ты решил начать изучение 3DGS, по факту это уже мертвый движок с небольшим комьюнити ностальгирующих. Он прикольный, но это для тех, у кого просто есть свободное время по фану
тот же юнити или UE как минимум можно использовать бесплатно, а так же они имеют просто бесконечную библиотеку ассетов. (гораздо лучше использования пиратской А7, а иначе не могу объяснить откуда у тебя неактуальная прошка, и такие элементарные вопросы, осуждаю)
3dgs же это для тех, кто хочет сделать всё сам, код\модели\текстуры, так как чего то готового и хорошего найти просто не получится. А из готовых шаблонов (темплейтов) каши не сваришь, поэтому писать свой код руками придётся обязательно.

Thanks. Now I will think about that.
Any additional suggestions are welcome.

Now as I have translated and (I hope) understood all the text...
1. UE was good - when it was UE2. I have no it.
2. UNITY - must not be newer than 3.5 - has no functions that I need.
3. My preference is to learn by examples. I look on exist templates as these examples.
4. All my work - models, textures, sounds, music, scripts, so on - I do by myself. Trash content from Unity Asset Store is not interest me.
5. If my question is 'so elementary' - where is the 'so elementary' answer on my 'so elementary' question?

oh, sorry
i saw location Russia in your profile, and that is why i wrote russian

5- elementary answer is - use screen_size\video_mode\video_aspect functions in your code

vec_set copies (sets) the second vector to the first, it is not a set of vectors. So...

vec_set(screen_size,vector(1600,900,0));

...changes the screen size to 1600 x 900.

I definitely recommend using the manual, and getting used to searching for things in there. But there is also AUM magazine which has a lot of working examples. You can see it on the left side of the main forum page. Note: A lot of the examples are from the older C-Script and will not work in Lite-C. With a bit of understanding they can usually be updated to Lite-C though.