I made simple flamethrower, but I have few questions:
1 - How to make collusions for flames?
First I just used trace in front of the player... but I want something else...
2 - How to make particles move away from weapon (or vertex)?
The way I did, they move only in X coordinates, whatever player turns to, I tried to use "vec_rotate" and other staff, no luck...

1 - maybe use c_scan from player with a cone around approximately the flames?

I guess, particles haven't any collisions detect.

But how to make player get damage from flames too?

maby with texture scanning;
c_trace(my.x,trace_flammes.x, SCAN_TEXTURE);.
Now when you make the flammes of the flammthrower out of alot of little spirets, you can just remove the flammes that touches the wall (or whatever) and with an easy else you can also scan the actors , with should get burned by the flammes.
When that happens, just create new flame spirets on the model, with got burned;
PARTICLE* hole = ent_decal(you,burn_wund,5,random(360));
or you even better you create new fire spirets on the model that got hit ,that expanse and creates the "burn_wund" particale at the places the flame on the model, that was created becouse of the flammes on the flammthrower.

1

you can C_trace from every particle along the velocity vector
This way you can perform collision detection on particles(this is slow).
you can also trace once, when you initialize the particle,
and store the hit position somewhere(particles will fade out when they reach this spot).
This is in most cases sufficient, as walls normally don't move.

2
some idea for moving direction:
vec_for_angle( temp, players_angle);
vec_normalize( temp, some_velocity);
effect(particle,1,weapons_vertex, temp);

1 - Good idea with traces, will try but I hope it'll be not to much slow...
2 - I already tried that, but didn't work

Random: FYI: I can't use decals

for the damage:
you can use C_trace with the ACTIVATE_SHOOT flag
then you write a shoot event, I think there are some examples in the manual.

I'll try thing with traces, sounds easy...
But what about making particles move away from specific model or vertex?

I dont know if it works but you can try it

when the player shoots with the flamethrower create a box (or a sphere, or...).
while firing, scale the box with the same speed, the particles are moving untill its scaled to the max range of the flames.
also while firing, set the angle of the box always to the direction the particles are moving.

now you should be able to use a simple collision detection

(why do all try the most complicated ways first?!)


[Edit]
... but it could be a problem if the player turns fast.
(i have to think about that...)

@problem 2)
using vec rotate should work... do you use the velocity vector of the particles?