For people who deals with CAD drawings, it’s not unusual to find the dimension and real size are different.

Why this happens and how can we deal with it?

1. the object is not parallel with the UCS plane

When we use DI to measure, it displays not only the distance but also increment in different directions, as shown in the following picture,

So if the object is not parallel with the UCS plane, which is to say the increment in the Z axis is not zero.

2. Draughtsman has modified the dimension

Sometimes it happens when the real size and the dimension are pretty much the same, for example, the dimension is 1000 and the real size is 998, the draughtsman may just modify the dimension for convenience.

3. The linetype scale of dimension style has been modified

Use dimension style to dimension, if the real size is the same as the dimension value, then we can say that the linetype scale has been modified.