Dimensional compensations for additive manufacturing

A system comprising:

• a processor;
• and
• a memory storing instructions executable by the processor to:
• receive object model data representing a first object to be generated by an additive manufacturing apparatus by depositing and selectively fusing first powder build material layers within a fabrication chamber above a second object to be or that has already been generated by the additive manufacturing apparatus by depositing and selectively fusing second powder build material layers within the fabrication chamber;
• determine an indication of an amount of fused build material of the second object in a second region of the fabrication chamber below a first region in which the first object is to be generated;
• determine a dimensional compensation value to apply to the object model data based on the determined indication, the dimensional compensation value is determined to compensate for inconsistency in thickness of the first powder build material layers when being deposited due to the amount of fused build material of the second object in the second region of the fabrication chamber below the first region;
• apply the determined dimensional compensation value to the object model data to derive modified object model data;
• and
• cause the additive manufacturing apparatus to generate the first object according to the modified object model data.

A non-transitory computer-readable data storage medium storing program code executable by a processor to perform processing comprising:

• receiving object model data representing a first object to be generated by an additive manufacturing apparatus by depositing and selectively fusing first powder build material layers within a fabrication chamber above a second object to be or that has already been generated by the additive manufacturing apparatus by depositing and selectively fusing second powder build material layers within the fabrication chamber;
• determining an indication of an amount of fused build material of the second object in a second region of the fabrication chamber below a first region in which the first object is to be generated;
• determining a dimensional compensation value to apply to the object model data based on the determined indication, the dimensional compensation value is determined to compensate for inconsistency in thickness of the first powder build material layers when being deposited due to the amount of fused build material of the second object in the second region of the fabrication chamber below the first region;
• applying the determined dimensional compensation value to the object model data to derive modified object model data;
• and
• causing the additive manufacturing apparatus to generate the first object according to the modified object model data.