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# How do you dimension a diameter on a line?!

kiarian_coohill
Member Posts:

**16**EDU
in Drawings

Fundamentals 3 - Exercise: Coffee Cup

Fallen at the first hurdle here. I can't figure out how to dimension this 125 diameter. It's a line. How do I go beyond the line to change the dim to a diameter?

I've read the hint, and I still haven't figured it out.

Fallen at the first hurdle here. I can't figure out how to dimension this 125 diameter. It's a line. How do I go beyond the line to change the dim to a diameter?

I've read the hint, and I still haven't figured it out.

0

## Comments

16EDU2,20516EDU16EDU171PRO16EDU3✭I am new to CAD and I am stuck! I cant figure out how to get the diameter on the mug, I've managed to do this one the wheel exercise but cant figure out how to do it again.

1,286See the "centerline dimension" section of this page:

https://cad.onshape.com/help/Content/sketch-tools-dimension.htm

To do this type of dimension, you'll first want to click the dimension tool, then click the point you want to dimension, then click the centerline, then move your mouse across to the other side of the centerline, then click one last time to place it. The key here is to move your mouse across the centerline after selecting both the entity to dimension and the construction line you want to use as a centerline.

579Hi calvin_george,

The trick to getting the diametric dimension is to select the construction line first, then the point you wan to be the diameter, and then to place the dimension on the opposite side of the construction line.

1. With the dimension command active, select the construction line

2. Select the outer point on the cup. This will start doing a horizontal point-to-line dimension. But don't place it yet.

3. Before placing it, move your cursor to the other side of the construction line. This will give a diametric constraint.

3✭3✭Thank you in advance

1,286The selection you are using for the revolve is the entirety of "Sketch 1". You should de-select the whole sketch (space bar or clicking the x next to that selection), and instead select just the inner area by clicking on it.