A fixture (104, 204, 304) for supporting an object (102, 202, 302) on a build platform of an additive manufacturing system, the fixture (104, 204, 304) being suitable to support an object (102, 202, 302), which is to be additively manufactured thereon, during its building process and comprising: a body (150, 250) having a hollow portion (152, 252) therein, an upper surface (154, 254) shaped to support the object (102, 202, 302) to be additively manufactured thereon by the AM system and a lower portion (156, 256) configured to be supported on the build platform of the AM system; wherein the hollow portion (152, 252) includes a plurality of vanes (172, 272) that define passages (174, 274) extending entirely through the body (150, 250) from the lower portion (156, 256) to the upper surface (154, 254) of the body (150, 250) and provide line of sight and access from the lower portion (156, 256) to a lowermost portion (158, 258) of an object (102, 202, 302) allowing a post-manufacturing process through the hollow portion (152, 252) of the body (150, 250), when the object (102, 202, 302) is supported on the upper surface (154, 254) of the body (150, 250); wherein the fixture (104, 204, 304) is additively manufactured and an object is additively manufactured so as to lay upon the upper surface (154, 254) and adhere to the fixture (104, 204, 304), the fixture (104, 204, 304) and the object (102, 202, 302) obtained by an additive metal powder melting process; wherein the upper surface (154, 254) includes a sacrificial cutting layer at an uppermost extent thereof and interposed between the fixture (104, 204, 304) and the object, the sacrificial cutting layer having a thickness configured for cutting by a cutting tool to remove the fixture (104, 204, 304) from the object (102, 202, 302), the sacrificial cutting layer formed by an additive metal powder melting process using adjusted AM system parameters so as to have a lower density than the additively manufactured object. a body (150, 250) having a hollow portion (152, 252) therein, an upper surface (154, 254) shaped to support the object (102, 202, 302) to be additively manufactured thereon by the AM system and a lower portion (156, 256) configured to be supported on the build platform of the AM system; wherein the hollow portion (152, 252) includes a plurality of vanes (172, 272) that define passages (174, 274) extending entirely through the body (150, 250) from the lower portion (156, 256) to the upper surface (154, 254) of the body (150, 250) and provide line of sight and access from the lower portion (156, 256) to a lowermost portion (158, 258) of an object (102, 202, 302) allowing a post-manufacturing process through the hollow portion (152, 252) of the body (150, 250), when the object (102, 202, 302) is supported on the upper surface (154, 254) of the body (150, 250); wherein the fixture (104, 204, 304) is additively manufactured and an object is additively manufactured so as to lay upon the upper surface (154, 254) and adhere to the fixture (104, 204, 304), the fixture (104, 204, 304) and the object (102, 202, 302) obtained by an additive metal powder melting process; wherein the upper surface (154, 254) includes a sacrificial cutting layer at an uppermost extent thereof and interposed between the fixture (104, 204, 304) and the object, the sacrificial cutting layer having a thickness configured for cutting by a cutting tool to remove the fixture (104, 204, 304) from the object (102, 202, 302), the sacrificial cutting layer formed by an additive metal powder melting process using adjusted AM system parameters so as to have a lower density than the additively manufactured object.