hook.Add("PlayerNoClip", "InvisibleNoClip", function(player)
    if (player.IsNoDrawn == nil) then
        player.IsNoDrawn = player:IsEffectActive(EF_NODRAW);
    end;

    if (player:GetMoveType() == MOVETYPE_NOCLIP) then
        player:AddEffects(EF_NODRAW);
    elseif (!player.IsNoDrawn) then
        player:RemoveEffects(player.IsNoDrawn);
    else
        player.IsNoDrawn = nil;
    end;
end);