Concave planes not marked as invalid

[LogicAndTrick]

When loading OBJ files or doing VM, faces that create concave solids are not marked as invalid.

Reproduction:

Sledge.BspEditor.Clipboard
{
    Solid
    {
        "ID" "2"
        "IsSelected" "True"
        "ParentID" "1"
        ObjectColor
        {
            "Color" "0 221 234"
        }
        Face
        {
            "ID" "7"
            Plane
            {
                "Normal" "0 -1 0"
                "DistanceFromOrigin" "0"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "1 0 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "0 0 64"
            }
            Vertex
            {
                "Position" "64 0 64"
            }
            Vertex
            {
                "Position" "64 0 0"
            }
            Vertex
            {
                "Position" "0 0 0"
            }
        }
        Face
        {
            "ID" "8"
            Plane
            {
                "Normal" "0 1 0"
                "DistanceFromOrigin" "64"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "-1 0 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "64 64 64"
            }
            Vertex
            {
                "Position" "0 64 64"
            }
            Vertex
            {
                "Position" "0 64 0"
            }
            Vertex
            {
                "Position" "64 64 0"
            }
        }
        Face
        {
            "ID" "9"
            Plane
            {
                "Normal" "-1 0 0"
                "DistanceFromOrigin" "0"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "0 -1 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "0 64 64"
            }
            Vertex
            {
                "Position" "0 0 64"
            }
            Vertex
            {
                "Position" "0 0 0"
            }
            Vertex
            {
                "Position" "0 64 0"
            }
        }
        Face
        {
            "ID" "10"
            Plane
            {
                "Normal" "0 0 1"
                "DistanceFromOrigin" "64"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "1 0 0"
                "VAxis" "0 -1 0"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "0 64 64"
            }
            Vertex
            {
                "Position" "64 64 64"
            }
            Vertex
            {
                "Position" "64 0 64"
            }
            Vertex
            {
                "Position" "0 0 64"
            }
        }
        Face
        {
            "ID" "11"
            Plane
            {
                "Normal" "0 0 -1"
                "DistanceFromOrigin" "0"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "-1 0 0"
                "VAxis" "0 -1 0"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "0 0 0"
            }
            Vertex
            {
                "Position" "64 0 0"
            }
            Vertex
            {
                "Position" "64 64 0"
            }
            Vertex
            {
                "Position" "0 64 0"
            }
        }
        Face
        {
            "ID" "12"
            Plane
            {
                "Normal" "0.8944272 0 -0.4472136"
                "DistanceFromOrigin" "28.62167"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "0 1 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "64 0 64"
            }
            Vertex
            {
                "Position" "64 64 64"
            }
            Vertex
            {
                "Position" "48 32 32"
            }
        }
        Face
        {
            "ID" "13"
            Plane
            {
                "Normal" "0.8944272 -0.4472136 0"
                "DistanceFromOrigin" "28.62167"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "0 1 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "64 64 64"
            }
            Vertex
            {
                "Position" "64 64 0"
            }
            Vertex
            {
                "Position" "48 32 32"
            }
        }
        Face
        {
            "ID" "14"
            Plane
            {
                "Normal" "0.8944272 0 0.4472136"
                "DistanceFromOrigin" "57.24334"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "0 1 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "64 64 0"
            }
            Vertex
            {
                "Position" "64 0 0"
            }
            Vertex
            {
                "Position" "48 32 32"
            }
        }
        Face
        {
            "ID" "15"
            Plane
            {
                "Normal" "0.8944272 0.4472136 0"
                "DistanceFromOrigin" "57.24334"
            }
            Texture
            {
                "Name" "aaatrigger"
                "Rotation" "0"
                "UAxis" "0 1 0"
                "VAxis" "0 0 -1"
                "XScale" "1"
                "XShift" "0"
                "YScale" "1"
                "YShift" "0"
            }
            Vertex
            {
                "Position" "64 0 0"
            }
            Vertex
            {
                "Position" "64 0 64"
            }
            Vertex
            {
                "Position" "48 32 32"
            }
        }
    }
}