A computer-implemented method comprising: obtaining data for three dimensional geometry of a part to be manufactured from a material by a hybrid additive and subtractive manufacturing system comprising an additive manufacturing tool and a subtractive manufacturing tool using a manufacturing process comprising a series of two or more stages, each of the two or more stages comprising adding the material with the additive manufacturing tool and removing some of the material with the subtractive manufacturing tool; the method being characterised in that it further comprises: simulating (310, 315), in accordance with the data and a physical property of the material, at least a portion of the manufacturing process that includes adding first material using the additive manufacturing tool in a first stage of the two or more stages and removing second material using the subtractive manufacturing tool in a second stage of the two or more stages, wherein the first stage precedes the second stage, wherein the second material includes a portion of the first material, wherein removing the second material comprises blending between the material added in the first and second stages, and wherein the simulating comprises simulating thermal effects of adding and removing the material in the first and second stages; adjusting an amount of the portion of the first material included in the second material based on results of the simulating, in accordance with the physical property of the material, to prevent deviation of the part from the three dimensional geometry, during the portion of the manufacturing process, that results in not enough material being available for the blending; and providing the adjusted amount for manufacturing the part by the hybrid additive and subtractive manufacturing system. obtaining data for three dimensional geometry of a part to be manufactured from a material by a hybrid additive and subtractive manufacturing system comprising an additive manufacturing tool and a subtractive manufacturing tool using a manufacturing process comprising a series of two or more stages, each of the two or more stages comprising adding the material with the additive manufacturing tool and removing some of the material with the subtractive manufacturing tool; the method being characterised in that it further comprises: simulating (310, 315), in accordance with the data and a physical property of the material, at least a portion of the manufacturing process that includes adding first material using the additive manufacturing tool in a first stage of the two or more stages and removing second material using the subtractive manufacturing tool in a second stage of the two or more stages, wherein the first stage precedes the second stage, wherein the second material includes a portion of the first material, wherein removing the second material comprises blending between the material added in the first and second stages, and wherein the simulating comprises simulating thermal effects of adding and removing the material in the first and second stages; adjusting an amount of the portion of the first material included in the second material based on results of the simulating, in accordance with the physical property of the material, to prevent deviation of the part from the three dimensional geometry, during the portion of the manufacturing process, that results in not enough material being available for the blending; and providing the adjusted amount for manufacturing the part by the hybrid additive and subtractive manufacturing system. simulating (310, 315), in accordance with the data and a physical property of the material, at least a portion of the manufacturing process that includes adding first material using the additive manufacturing tool in a first stage of the two or more stages and removing second material using the subtractive manufacturing tool in a second stage of the two or more stages, wherein the first stage precedes the second stage, wherein the second material includes a portion of the first material, wherein removing the second material comprises blending between the material added in the first and second stages, and wherein the simulating comprises simulating thermal effects of adding and removing the material in the first and second stages; adjusting an amount of the portion of the first material included in the second material based on results of the simulating, in accordance with the physical property of the material, to prevent deviation of the part from the three dimensional geometry, during the portion of the manufacturing process, that results in not enough material being available for the blending; and providing the adjusted amount for manufacturing the part by the hybrid additive and subtractive manufacturing system.