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OBJ
A common polygon mesh file format that can store geometry and, in some cases, texture or colour references.
Rapid Prototyping Glossary
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Definitions for commercial rapid prototyping, production, machining, casting, moulding, finishing and inspection terms.
Offset
A programmed correction applied to account for tool length, tool diameter, wear or work coordinate location so the machine cuts to the intended dimensions.
On-axis hole
A turned hole concentric with the rotational axis of the part.
On-demand manufacturing
A production model in which parts are made to order rather than held in stock, commonly used for prototypes, bridge production and service-bureau machining.
On-machine probing
Using a spindle or table probe to locate workpieces and verify dimensions on the machine.
Orange peel
A wavy cosmetic texture resembling citrus skin, often seen in paint or imperfect moulded surfaces.
Orbital sanding
A finishing operation using a random-orbit abrasive tool to remove marks and create a non-directional swirl finish.
Orthotropic properties
Material properties that differ along three mutually perpendicular directions.
Outgassing
The release of trapped gases or volatiles from a material, important in vacuum, curing and coating processes.
Overbuild allowance
Intentional extra stock or thickness added so the part can be machined or polished back to target size.
Overcut
Excess material removal beyond the intended boundary, often at corners or due to toolpath behaviour.
Overflow
A deliberate extra cavity or excess region used to collect material or improve fill before trimming.
Overmoulding
Moulding one material over another substrate or previous moulding to create soft grips, seals or multi-material parts.
Oxidation
Reaction with oxygen that can form an oxide layer, alter surface condition or affect bonding.