i am new to blender game and was wondering how to make blood in the game. i have seen no tutorials as to how to make it react to enemy meshes with blood spots and if i cut off an arm if it could gush blood. im assuming it has something to do with the fluid simulator but am completely lost i am new to blender too as well as this site soo plz be gentle.
Welcome! 
There are a number of different ways this could be simulated. Have you worked with any other engines in the past? (This might make things easier to understand)
As for the fluid simulator, that is not something you can run within the BGE. (Only for standard renders) Very few game engines actually feature a real-time fluid simulator because very few machines can actually handle it at the moment.
April fools contender.
Um… how so? This person is new to the forums and they are asking a fairly legitimate question.
yeah im not an april fools guy i just figured out ho this works and all im working on a game and wanted to know how to make blood.
If you are still interested, im still willing to help.
yes very much soo im still pretty confused. i would guess it would be the fluid similator no i would bake it our and have it play the sim everytime a bullet hit a mesh?
Like this?
That was an old project (I haven’t got it any more, sorry) which used simple “gibs” of bones + many planes of “blood” set to “halo” material (always faces the camera) added via add object actuator.
Each plane has a simple animation so that it gets bigger and fades out at the same time. They also have gravity so they fall down.
The gibs are set to disappear after a few frames otherwise it’s obvious how low quality they are.
The whole thing can be quite loose and low quality because it is gone in a few seconds. The blood stain on the floor can stay or be removed, it’s up to you.
If you want to add some gore to your game, be aware that in some countries you won’t be able to sell your game because of strict rules about what can and can’t be shown on TV and in video games.
Smoking - That is a brilliant simulation, looks very well made!
to give more insight i have a make human model that i customized and i wanna take the skin textures possibly in gimp and make it look more like a zombie as far as the textures go. so far i just wanna create a minimal viable product so i can at least prototype it. the problem is can find numerous tutorials on everything else i like what you did there with the chunks and stuff but what im not quite sure on is actually having when a gun shoots how to make blood come naturally from the wound. i have some other ideas as where to take the project but since im still learning all the basics and actually using them its a little difficult and i have yet to find a good one that explains how to make gore such as described. i dont even have an idea where to start other then maybe the fluid simulator and baking it would be my only logical guess. as for your model and animation there i can only hope to achieve something of that nature since im still very bad at blender but working hard to achieve something better so any help would be very much apreciated!
Fluid simulation is not going to give you what you want here.
What you want to use is a particle system. Take a look at just about any game that has ‘spraying blood’ in it: You’ll notice that the blood is not actually ‘fluid’, but more like a collection of blood-splat-shaped sprites which are moving in a stream, to imitate moving fluid.
I would look into creating yourself a little particle system. Look into how to do things more ‘innocent’ than gore: Smoke, explosions, fireballs, magic sparkles: They all use particles.
Here is something to get you started. How to get started with particles.
This covers how to create bullet holes. Combine these theories with the particle system above, and change your bullet holes to blood splats 
thanks for you help it really did help me much
Those are based on Socials FPS, I change the bullet-hole texture to blood. I been using them for a while. But, the bullet-hole or blood don’t stick to a moving object. Is there anyway to parent the bullet-hole/blood (via script) to a moving object?
It works okay if you have one zombie on an inactive layer that you are going to spawn. Then you could just use logic bricks on the bullet-hole/gore plane to set parent to the zombie.
But what if you have a lot of different enemies that you want to spawn. Can you set parent to the hit object?
And if you use the script to cast a ray (Like Socials) it will hit the zombies collision box. Not the zombie mesh itself.
So to expand on the OPs question, how do you guys place blood-holes on a moving mesh? Replace mesh?
To the OP. If you find a way, would you please let us know how you did it?
Having blood decals applied to a dynamic model is a whole different can of worms than placing decals on static walls. Simply parenting the blood plane to the zombie is not going to work.
The old-school solution to this is to use “pain skins”, an alternate texture (or in the case of BGE, a mesh with an alternative material) that depicts the character with blood/cuts/bruises/etc. When the character reaches a certain damage threshold, they switch over to their pain skin.
If you want to get more detailed than that, you can create each body part as a seperate mesh, and apply pain skins to affected areas. With this though, you will have to implement some sort of locational hit detection, rather than one bounding box for the zombie.
Alternatively, you can look into ‘Texture Splatting’ which may provide a solution. Hunt around, there are many articles/tutorials on the subject. I’ve only seen this done on static terrain, but it might work with dynamic meshes also…
Rigged characters are very difficult to work with. Texture splatting usually relies on vertex colors, which can’t be set on a rigged character. Breaking the character’s mesh in to sections and then doing mesh replace would be the best way to do that one on a rigged character.
Or you can parent simple primitives to the character’s bones if you want to use those for hit detection and blood splatter placement. Make the object invisible though…
Simply parenting the blood plane to the zombie is not going to work.
For sure, my zombie walks away leaving blood holes hovering in space. LOL.
That’s the problem.
Pain skins sound painful to make work. LOL But I’ll try it. Thanks for the jnfo.
Or you can parent simple primitives to the character’s bones if you want to use those for hit detection and blood splatter placement. Make the object invisible though…
Sounds like a good idea. I’ll give that a try.
Their secret? The blood is always there. On everything. You just can’t always see it.
This article talks about blood splatter and gore, while I’m not familiar with the subject or the method but I think they have the diffuse texture overlay on the blood texture that are only revealed when the conditions are met, I recalled a similar technique was used in star citizen to demonstrate dynamic damage, it also involved different sets of damaged textures depending on what triggers it, I think similar thing can be done in blender but it most likely will take alot of coding
OK, I got it working. (kind of) here’s what I did
1 select zombie mesh.
2 tab into edit mode,
3 select a face where i wanted a blood hole, Shift “D” to duplicate.
4 “P” to separate selection. name it “Bloodhole” Paint or map blood to it or make it look like torn flesh.
5 Tab to object mode,
This just makes sure that the bloodhole matches the contour of the mesh.
Or, just add your own mangled flesh.
6 add an Empty.
7 snap the empty to the bloodhole. (Control “S” )
8 parent the empty to the Armature, chest bone, for example.
9 Parent the bloodhole to the empty.
10 select the empty and move it into the zombies chest and out of sight, (bloodhole should move with it)
11 on frame 1 select the empty press keyboard “I” LOC
12 change to frame 2 press “I” LOC.
13 play the animation when the zombie is hit
In my case the hitbox takes the damage using a float property called hp 3.00
So the zombie can take 3 hits before it dies.
on the empty I copy the hitboxes hp property, then use logic bricks to play animation.
Or you could send a message, whatever works for you.
Property hp equals 2----------and------------Action play, start 1, end 2. This moves bloodhole out of the chest and into sight.
do the same for a second and third bloodhole.
Now zombie can move without losing the gore. 
hp<=0 zombie dies.
I’m thinking a pain skin can be used the same way.
That looks awesome. Off topic, how did you get the spawning ragdolls to work? Is it a special build of blender?
On topic, I thought I’d post an example of the pain skin mechanic:
This is for robots, so it shows a damage skin, but the idea is virtually the same for human characters or zombies.
Each body part is separate but all parented to the armature. The origin should be in the center to match the armature, I’ve moved it on one of the models to show the different sections more clearly.
When your character gets arm damage, swap the arm mesh for the damaged one, when they get leg damage do the same with the legs. You can split your mesh up in to as many different sections as you like to show damage in different areas.