A　well-fitting　bra　provides　adequate　and　exceptional　support　of　the　breasts　and　the　desirable　body　shape　for　the　wearer　but　would　not　exert　excessive　pressure　onto　the　breasts.　Among　the　different　design　features　of　bras,　the　materials　selected　for　the　bra　cups　are　a　key　element　for　enhancing　breast　support　and　improving　the　perceived　comfort.　This　paper　proposes　a　subject-specific　model　based　on　numerical　simulation　to　investigate　the　influence　of　different　types　of　bra　cup　materials　on　the　shape　of　the　breasts　and　amount　of　pressure　on　the　breasts.　The　study　comprises　three　phases.　The　first　phase　is　the　development　of　a　subject-specific　contact　model　and　simulation　of　the　bra-wearing　process.　The　second　phase　is　the　construction　and　analysis　of　three　models　with　different　bra　cup　materials　(knitted,　woven　and　foam)　to　compare　their　shaping　effects　on　the　breasts　and　the　corresponding　amount　of　applied　contact　pressure.　The　third　phase　uses　the　validated　numerical　model　to　simulate　the　use　of　a　series　of　virtual　bra　cup　materials,　their　impact　on　the　shape　of　the　breasts,　and　the　associated　bra　pressure.　It　is　found　that　a　stiffer　fabric　has　a　better　performance　in　reshaping　the　breasts　and　reducing　the　amount　of　pressure　from　the　straps　onto　the　neck　for　a　halter-neck　bra　but　distributes　a　higher　amount　of　pressure　at　the　bottom　part　of　the　breasts.　An　overall　better　performance　of　reshaping　the　breasts　is　achieved　by　increasing　the　tensile　strength　of　the　bra　cup　material.　Nevertheless,　the　small　change　in　the　shaping　effects　can　be　negligible　after　the　Young＇s　modulus　reaches　about　1.5　MPa.　Among　the　four　measured　variables,　it　is　more　useful　to　measure　the　gathering　of　the　breasts　and　depth　of　cleavage　than　the　lifting　of　the　breasts　to　determine　the　amount　of　breast　deformation　caused　by　a　bra.　The　newly　developed　finite　element　model　for　contact　analysis　in　this　study　provides　a　better　understanding　on　the　interactive　process　between　the　breasts　and　the　bra　by　predicting　the　deformation　within　a　variance　of　6.8　%　in　comparison　to　the　experimental　results　of　the　contact　pressure　with　the　same　trend　and　magnitude.　Numerical　simulations　can　therefore　facilitate　decisions　on　the　type　of　fabric　used　for　bra　designs　that　provide　optimal　fabric　pressure　and　other　stretchable　apparel　products　that　take　both　the　shaping　effect　and　wear　comfort　into　consideration.