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When converting from Matrix33 to Matrix44, the third row and column remain as identity:
` [ a b c ] [ a b 0 c ] [ d e f ] -> [ d e 0 f ] [ g h i ] [ 0 0 1 0 ] [ g h 0 i ] `*
When converting from Matrix33 to Matrix44, the third row and column remain as identity:
` [ a b c ] [ a b 0 c ] [ d e f ] -> [ d e 0 f ] [ g h i ] [ 0 0 1 0 ] [ g h 0 i ] `*