How to ignore "Air" material when using :FindPartOnRay()?

Hi I am trying to use FindPartOnRay() to detect terrain type of "Mud" but I keep getting "Air."

mouse.Move:Connect(function()
	local ray,point,surfaceNormal,material = game.Workspace:FindPartOnRay(Ray.new(game.Workspace.Camera.CFrame.Position,mouse.Hit.Position)
	print(material)
end)
--Always prints air, even when pointed at a plastic brick or Mud terrain

mouse.Move:Connect(function()
    local ray,point,surfaceNormal,material = game.Workspace:FindPartOnRayWithIgnoreList(mouse.UnitRay,{Enum.Material.Air})
    print(material)
end)

The "FindPartOnRayWithIgnoreList" is what you were looking for.

Also just found the possible reason why Enum.Material.Air does not work for an ignore list, it is set to not browsable https://wiki.roblox.com/index.php?title=API:Class_reference/ReflectionMetadata

I came up with another idea, but it didn't work, I'll put the code here anyway (it does work for other applications)

I made a region3 from the camera's position to the mouse position and used Terrain:ReadVoxels() to get the terrain along the path of the ray, but the problem in this case is that Enum.Material.Air is not able to be detected by ReadVoxels

mouse.TargetFilter = workspace.Part

function ignoreList(first,last)
    local region = Region3.new(last, first)
	print(region.CFrame," SIZE ",region.Size)
	workspace.Part.CFrame=region.CFrame--this places a part in the middle of the region so you can visualize where the region is
    region = region:ExpandToGrid(4)
    local material,occupancy = game.Workspace.Terrain:ReadVoxels(region, 4)
    local size = material.Size
	local allMats = {}
    for x = 1, size.X do
    	for y = 1, size.Y do
    		for z = 1, size.Z do
    			allMats[#allMats+1]=material[x][y][z]
				
    		end
    	end
    end
	return allMats
end