I’ve been working for over a week on a problem with a projectile asset in my project. So far no solution was successful. I’m creating an environment where the user can test his shooting skills using ballistic notions. The distance with targets can range from 100m up to 4000m. Although UE4 has a strong projectile physic engine it is not designed to address very specific situations with projectile trajectory at extreme long ranges (2000m+) such as load type, altitude, temperature, barometric pressure, wind drift, bullet spin drift, coriolis effect, supersonic/trans-sonic/subsonic transitions, etc. In order to answer these factors I designed vector spline trajectories that are based on real projectile data generated by a professional ballistic engine used by the military. The splines have a curve that is accurately designed according to specific ballistic situations at gun range and showcase several variations throughout their whole length that can’t be reproduced by UE4 physic engine.
I’m using the Cubit Ballistics FX module to generate ricochets, particles/decals/etc, a rendertarget 2D for bullet holes and a score system to calculate shots accuracy. What I’m trying to do is to get the Cubit projectile to follow my splines instead of using the original “Projectile Movement” physic. I was able to make “Projectile follows spline” to work and I can send the projectile exactly where I want it to go according to real-life ballistic data. But the projectile collision is not working properly. When I enter 0 for velocity in projectile movement the projectile is following the spline properly and trace debug is showing hit detection on target but the score, ballistic FX and see-through hole are not triggering. The projectile simply continues its course until the end of its life. If I enter 40 000 for velocity in projectile movement all the projectile reactions mentioned above start to work. However I cannot input a speed in projectile movement since it will distort predefined spline trajectory and the projectile will go too fast. This data has to remain 0.
My question is “Why projectile FX work with velocity at 40 000 and not working when input speed is at zero?”. If the rifle is sending the projectile without a spline all the FX work, even at a speed of 1, but if the rifle sends the same projectile which movement follows the spline, FX won’t work unless speed is set to 40 000.
The following video provides an idea of the situation:
1min10sec timecode illustrates the problem with projectile speed.
Cubit ballistic FX module used in my project:
I’d appreciate any help you could provide. Thanks!