[Slowpoke] Thread about bullet modeling Thread - OccupationCS: Source mod for Half-Life 2

Hi EnterpriseG, I'm currently making a design which handles different depths of gameplay systems.

(And also I am a fan of a damage system you've created.)

For example, having an Simple (Damage System) means there wouldn't be such thing like vital damage or shock - it's all measured on simple 100% gauge that depletes on hit.

While having Advanced means that such stuff as getting your lungs hit means you not only start bleeding, but might suffocate from sheer awesomeness getting such internal being damaged.

All of that can be transferred to every gameplay mechanics, be it Melee combat, Ranged combat, Usage of items, Inventory work...

Being probably not the best brain, all I could find is some stuffy formulas and lectures about kinds of cavities/bullet types/etc. Which are simply only show the results, while the matter is that I just want to see the factors to reproduce the ways to achieve one or another result.

And I'm just making design for fun and as hobby+educational reasons.

If you see this, can you answer these questions?

Complex Bullet Ricochet / Penetration / Bore / Exit

1. Ricochet. As I understand it's based on the bullet jacket/core hardness+energy+cos(angle to normal). Nothing advanced like normalisation is needed for my design.
2. Penetration. How do you even calculate this one? I found one formula and have certain constants for both armor and body surrogate, yet I don't understand how to manage this one part. As I understand its based on jacket/core hardness, bullet angle and energy...
3. Bore. How to manage stuff at this point? How to model what happens to bullet (deceleration, penetration of internals...)? I mean, should I do the decelleration of bullet linear or make it dependable on energy/density/hardness balance?
4. Lodge/Thru&Thru. Those I kinda understand. Well, 95% of the meaning. Lodge means that bullet stops completely, body receives 100% of the impact energy... While T&T - "overpenetration". Yet how do I do these checks?

Projectile Fragmentation / Expansion

1. How do I manage Fragmentation? I have material, then check it up with density/hardness or what? Charge of the bullet and core material (if its jacketed)? And how to calculate fragments? Should random work here? Or its partially based on energy/load on bullet?
2. How do I manage Expansion? As I understand, its like Fragmentation, except the soft point getting destroyed and mushrooming the cavity?

Energy/Cavity Based Damage

1. How's this one calculated? Is the energy transfer to body linear? I remember its like no more that 25j/cm standart. And 70-80 J being the min cap to damage the skin/body.
2. How's this one calculated? Cavities being permanent/time-pulsing/impact based?

Overall damage: how to calculate? I'd like to see bullet math basic on those, even if its non understandable differential equations.

For example: .22LR Hyper Velocity round.

I know that it weights ~1,9-2,5 gramm, has Muzzle Velocity of ~435 meters per second (totaling ~180 Joules), type is Copper Jacketed HP bullet.

For example, it hits right arm with no armor/clothes on.

I designed it like:

1) Penetration/Energy/... basic calculations, which depend on a bullet char's and answers those questions:

• Penetration check. How approx. long the cavity will be if the way is a straight line.
• Energy check

2) Bullet trail and cavity/-ies, based on what was achieved in 1 point, depends on bullet char's and answers those questions:

• What was hit? Was it Skin/Muscle/Vitals/Bones?
• How strong the damage was from physical perspective?

3) Damage types, those are based on what was achieved in 2 point:

• Penetration - damage caused by bullet penetrating/putting enough pressure for part to be "hit"
• Slash - damage caused by bullet/fragments area that literally cuts-into.
• Impact - damage caused by deflection, penetration, expansion of said bullet and whats so ever...

4) Distribution of said damage between Vitality and whatever damage pool I come up, based on 3 point.

What should I do with said bullet that hit the said arm?

P.S. If you do not want to respond questions like "How did you do that particular stuff?", I can understand that.

If you managed to do that and don't want to disclose the way you done it, fine

(you ported it to another mod which is still in dev, so you probably want to keep this kind of info closed, cause its yours).

Just put into direction where to find all that stuff.

Because lurking over 500 sites didn't gave me anything besides "use compelling and hard to use modelling softwares that cost alot" or formulas that are simply usable in one situation from 10.

And simple stuff like physics formulas or some other-worldy "true or false?" formulas like knock down ones are something to blow my head off, cause they don't show up actual bullet interacting with the body. Which is kinda the goal of the advanced system - bullet that hits particular bodypart does particular job instead of just applying damage points to player.