Ordinate dimensions, also known as baseline dimensions, are a type of dimensioning system used in technical drawings and engineering design to define the location of features or objects relative to a common reference axis or baseline. Instead of providing individual dimensions for each feature’s location, ordinate dimensions reference a common starting point or origin, often called the “zero point,” and indicate the horizontal or vertical distance of each feature from that point.
Ordinate dimensions are appropriate to use in situations where multiple features or objects share a common reference axis and need to be accurately located relative to each other. This system simplifies the dimensioning process and reduces the chances of errors, as the dimensions are referenced from a single point, eliminating the need to provide separate dimensions for each feature’s position.
Advantages of using ordinate dimensions include:
- Clarity: Ordinate dimensions provide a clear and organized representation of the relative positions of features, making it easier for manufacturers and fabricators to interpret the drawing.
- Consistency: Since all dimensions are referenced from a single zero point, there is less room for inconsistencies or errors in dimensioning.
- Simplicity: Ordinate dimensions can simplify complex drawings by reducing the number of individual dimensions required.
- Time-saving: Drawing time can be reduced when using ordinate dimensions, as there is no need to duplicate similar dimensions for multiple features.
Ordinate dimensions are commonly used in scenarios such as:
- Hole patterns: When specifying the locations of holes in a pattern, ordinate dimensions can be employed to indicate the distances of each hole from a reference point.
- Symmetrical features: If a drawing contains symmetrical features that are equidistant from a centerline or baseline, ordinate dimensions can efficiently communicate their positions.
- Multiple identical components: When creating drawings for components that are identical but positioned at different locations, ordinate dimensions can simplify the dimensioning process.
- Consistent feature spacing: In assemblies or designs with a repetitive pattern, ordinate dimensions help ensure consistent spacing between features.
It’s important to note that while ordinate dimensions are effective for certain situations, they might not be suitable for all types of drawings. Complex geometries or irregularly spaced features might require individual dimensions for accuracy.