This should do it -

Set-ExecutionPolicy RemoteSigned

[Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.Smo")

Function Get-DatabaseFilesBySpaceAvailable ([Microsoft.SqlServer.Management.Smo.Server] $SmoSqlServer

, [decimal] $sizeThreshold=0.80)

{

$sqlServer.Databases | Where-Object{$_.Status -eq "Normal"} `

| Select-Object FileGroups -ExpandProperty FileGroups `

| Select-Object Files -ExpandProperty Files `

| Where-Object {$_.MaxSize -gt -1} `

| Where-Object {$_.UsedSpace -gt ($_.MaxSize * $sizeThreshold)} `

| Select UsedSpace,Size,MaxSize,FileName

}

$sqlServer = New-Object("Microsoft.SqlServer.Management.Smo.Server") "Server\Instance"

Get-DatabaseFilesBySpaceAvailable -SmoSqlServer $sqlServer| FT -autosize