I see. You're using an indexer and you can't translate 'this' to a property because properties don't allow multiple arguments.
If you don't want to use your new class: to get the value just use: bool value = aVt[x, y, z]; and to set the value use e.g.: SetaVt(1, 2, 3, true);
public void SetaVt(int x, int y, int z, bool value)
{
if (value == false)
{
if (aVt[x, y, s])
{
progressMade = true;
}
}
aVt[x, y, s] = value;
}