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How do I make a bullet marking script?

Asked by

9 years ago

I'm creating a FPS, making guns, having no problems except for one thing. When I shoot it, how do I make it so that a bullet mark appears on the surface of the part shot at? I know you have to create a part, and insert a decal with the bullet mark, but how do I get to know which surface my bullet has hit? Just to let you know, I'm using Ray Casting, not some body velocity thing.

Please either tell me how to get the surface of the object, or write a simple example script which makes a bullet mark on a surface when the ray has collided with a Part.

Thank you very much if you could help. I'm not really asking for scripts, more like help.

Well why not use a Touched Event on the bullet? And when it touches something the mark that appears on that surface is a part that perhaps gets welded to that surface? You should learn how to do welds with scripts and then do that or maybe you could make it so a part just gets CFramed to that position where the bullet colides and then the part is anchored... But then I was thinking if the player m KingLoneCat 2642 — 9y

I need to get the correct surface for the decal to be on. Touched events are not good for FPS's, they do not execute as fast as Ray Casting. There will be physics collision problems, whereas Ray Casting has none. OMEGA27304 8 — 9y

1 answer

Answered by

XAXA 1569

9 years ago

You may be familiar with the first two return values of FindPartOnRay: the part it hit and the point of intersection. There is a third value that you're ignoring, which is the surface normal. The surface normal is a one-stud long vector which is perpendicular to the face of the object.

Here's a picture I drew to illustrate what I'm talking about.

As you can see, no matter the angle of the ray, as long as they hit the same surface, their surface normals will be parallel. This is useful because this determines which direction the bullet hole will be facing.

Now assuming that you've already casted the ray, this is one way of making bullet holes:

01--Creating the bullet hole which will be cloned every time a hole needs to be made
02local bulletholepart = Instance.new("Part")
03bulletholepart.FormFactor = "Custom"
04bulletholepart.Size = Vector3.new(1, 1, 0.2)
05bulletholepart.Anchored = true
06bulletholepart.CanCollide = false
07bulletholepart.Transparency = 1
08 
09local bulletholedecal = Instance.new("Decal", bulletholepart)
10bulletholedecal.Face = "Front" -- you want it to be in front of the part for later
11bulletholedecal.Texture = "http://www.roblox.com/asset/?id=2078626" --  a bullet hole decal I found 
12 
13function shoot()
14    -- TO-DO: cast the ray
15    local hit, pos, normal = game.Workspace:FindPartOnRay(ray)
16    -- If I hit a wall, then
17        local bullethole = bulletholepart:Clone()
18        bullethole.Parent = game.Workspace
19        bullethole.CFrame = CFrame.new(pos, pos + normal) -- the most important part: this sets the CFrame of the bullethole so that it's nearly flush with the wall. 
20        game:GetService("Debris"):AddItem(bullethole, 10) -- automatically remove the bullet hole after 10 seconds
21    -- TO-DO: do damage if it hits a player, etc.
22end
 View all 22 lines...

Take note that you will have to add the bullet holes to the ignore list or else the bullet holes will stack with each other -- I'll leave that up to you.

Thank you so much. I was just about thinking of doing some ultra bothersome maths where you divide the part into 6 Vector3 values, each 0.2 studs thick, then attempting to position the bullet hole to one of the 6 values depending on where my ray hit. I woulda died. OMEGA27304 8 — 9y

Please accept the answer :) XAXA 1569 — 9y

four years ago is anybody reading this? botw_legend 502 — 4y

i am Dan_PanMan 227 — 4y

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same botw_legend 502 — 4y

wait... botw_legend 502 — 4y

that was MY question lol botw_legend 502 — 4y

don't even remember asking it a month ago botw_legend 502 — 4y

and that was 10 days ago ;p botw_legend 502 — 4y

same here IEntity_303I 80 — 4y

yup CatastrophicDinosaur 4 — 3y

How do I make a bullet marking script?

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