Verlet Cape

local next=next
local gravity=0.09
local friction=0.7
local bounce=0.8
local player=game.Players.LocalPlayer
local torso=player.Character.Torso
local function dist(p0,p1)
    local dx=p1.CFrame.x-p0.CFrame.x
    local dy=p1.CFrame.y-p0.CFrame.y
    local dz=p1.CFrame.z-p0.CFrame.z
    return math.sqrt(dx*dx+dy*dy+dz*dz)
end
local points={}
local joints={}
local function createPoint(x,y,z,pinned)
    local t = {x=x,y=y,z=z,oldx=x-0.4,oldy=y-0.4,oldz=z-0.4,pinned=pinned}
    points[#points+1]=t
    return t
end
local function createJoint(point1,point2,distance,line)
    local t = {point1=point1,point2=point2,distance=distance,line=line}
    table.insert(joints,t)
end
local function drawLine()
    for i=1,#joints do
        local j=joints[i]
        local line=j.line
        if not line then
            line=Instance.new("Part",workspace.CurrentCamera)
            line.BrickColor=BrickColor.new("Really black")
            line.Anchored=true
            line.CanCollide=false
            line.BottomSurface="Smooth"
            line.TopSurface="Smooth"
            local mesh=Instance.new("BlockMesh",line)
            mesh.Scale=Vector3.new(0.001,1.3,1.2)
            j.line=line
        end
        local dx=j.point2.x-j.point1.x
        local dy=j.point2.y-j.point1.y
        local dz=j.point2.z-j.point1.z
        local distance=math.sqrt(dx*dx+dy*dy+dz*dz)
        line.Size=Vector3.new(0.1,0.4,distance)
        line.CFrame=CFrame.new(Vector3.new(j.point1.x,j.point1.y,j.point1.z),Vector3.new(j.point2.x,j.point2.y,j.point2.z))
        *CFrame.new(0,0,-distance/2)
    end
end
local width=9
local height=15
local l=0.25
for y=1,height do
    for x=1,width do
        createPoint(l*x,25-l*y,0,y==1)
        if x>1 then
            createJoint(points[width*(y-1)+x-1],points[width*(y-1)+x],l)
        end
        if y>1 then
            createJoint(points[width*(y-2)+x],points[width*(y-1)+x],l)
        end
    end
end
local function updatePoints()
    for i=1,#points do
        local p=points[i]
        if not p.pinned then
            local vx=(p.x-p.oldx)*friction;
            local vy=-((p.y-p.oldy)*friction);
            local vz=(p.z-p.oldz)*friction;
            p.oldx=p.x
            p.oldy=p.y
            p.oldz=p.z
            p.x=p.x+vx
            p.y=p.y-vy
            p.z=p.z+vz
            p.y=p.y-gravity
            if p.y<-1 then
                p.y=0
                --p.oldy=p.y-vy*bounce;
            end
            local pos=torso.CFrame:inverse()*Vector3.new(p.x,p.y,p.z)
            if pos.z<0 then
                pos=torso.CFrame*CFrame.new(p.x,p.y,0)
                p.x=pos.x
                p.y=pos.y
                p.z=pos.z
                p.oldx=p.x-vx*bounce;
                p.oldy=p.y-vy*bounce;
                p.oldz=p.z-vz*bounce;
            end
        end
    end
end
local function updateSticks()
    for i=1,#joints do
        local j=joints[i]
        local dx=j.point2.x-j.point1.x
        local dy=j.point2.y-j.point1.y
        local dz=j.point2.z-j.point1.z
        local distance=math.sqrt(dx*dx+dy*dy+dz*dz)
        local difference=j.distance-distance
        local percent=difference/distance/2
        local offsetX=dx*percent;
        local offsetY=dy*percent;
        local offsetZ=dz*percent;
        if j.point1.pinned or j.point2.pinned then
            offsetX=offsetX*2
            offsetY=offsetY*2
            offsetZ=offsetZ*2
        end
        if not j.point1.pinned then
            j.point1.x=j.point1.x-offsetX
            j.point1.y=j.point1.y-offsetY
            j.point1.z=j.point1.z-offsetZ
        end
        if not j.point2.pinned then
            j.point2.x=j.point2.x+offsetX
            j.point2.y=j.point2.y+offsetY
            j.point2.z=j.point2.z+offsetZ
        end
    end
end
game:service'RunService'.RenderStepped:connect(function()
    for i=1,width do
        local p=torso.CFrame*CFrame.new(-1+0.25*(i-1),1,0.75)
        points[i].x=p.x
        points[i].y=p.y
        points[i].z=p.z
    end
    updatePoints()
    for i=1,10 do
        updateSticks()
    end
    drawLine()
end)