Ordinate Dimensions
Measure many points from one point. An ordinate dimension is the distance across, or up, from a chosen origin point to another point. A shop drawing often gives hole and edge positions this way, all from one corner, so the sizes never add up errors.
When to Use It
- Place holes or slots by their distance from one corner of a plate
- Size a stepped outline from one datum edge
- Keep many points tied to one origin, so moving the origin moves them all
Step by Step
- Open a sketch (see Planes and Faces). Sketching is part of modeling, which comes with the Pro plans.
- On the Sketch tab, click Advanced, then Ordinate.
- Choose what to measure in Measure: Horizontal (across) gives each point its distance across the screen, Vertical (up) its distance up the screen, and Both one of each.
- Press Sketch origin to measure from the origin of the sketch, or click the point to measure from: an end, a corner, a centre, the middle of a side, or a point. It shows as a large dot.
- Click each point to dimension. Each click adds the dimensions at the size the sketch has now, so nothing moves. Each number sits at the end of a short line drawn from its point, all lined up together, with a 0 at the origin point.
- Click a number to type a new size. The point moves to that distance from the origin point and the sketch solver keeps the other relations true. The box can also switch a dimension to Aligned, or to a reference dimension.
- Press Pick the point to measure from to start a new set from another point. Press Done (or Esc) when finished; the dimensions stay.
Things to Know
- Ordinate dimensions are ordinary driving dimensions. They are saved with the sketch, come back when you open it again, are listed in Edit, Relations as Horizontal distance or Vertical distance, can be named and used in Equations, and one Undo takes back each click.
- A point keeps the side it is on. If it is left of the origin point, typing a new size keeps it on the left.
- If the sketch already sets that distance (for example a line held to a length from a point already dimensioned), the new dimension would over define the sketch. It is added as a reference dimension instead: grey, in brackets, showing the size without controlling it. See Reference Dimensions.
- A point straight above or below the origin point has a horizontal distance of zero, and a point level with it a vertical distance of zero. A zero distance is not added: use a Vertical Points or Horizontal Points relation to hold it so.
- The same dimension twice on one point is refused.
- Stretch updates them: with Dimensions take the new sizes ticked, an ordinate across the window takes its new size. Move, Rotate and Scale do not: each ordinate keeps its size, so the solver holds the point to it and may refuse the move.
Limits
- The numbers are drawn level with the screen. Each set lines up just past the farthest of its points, above them for horizontal ones and to their right for vertical ones.
- An older version of the program opens these as plain horizontal and vertical distances, with the same sizes.