Scaling to a snap point or a known dimension

I have two cylinder. One above the other. The lower one has a bigger diameter.
I’d like to make the base of my upper cylinder, scaling it to the same dimension of the lower one.

How should I do?

When using the scale tool you can use specific dimensions by adding the Unit to what you type.
So if you scale in one direction and type 1.35m and hit enter it will scale to exactly that in that direction.

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I didn’t know about it :wink:
thank you so much.
So, being a circle, the measure i insert will be a diameter, right?

An interesting question because I often have to do something similar.

Say you have a component with a particular dimension of X and you have a line with dimension Y. You want the component’s dimension X to be scaled up/down to match dimension Y. I’ve always imagined there was an elegant and simple way to do that, but in practice I end up measuring both and using the resulting fraction when scaling the component.

I try the solution suggested by Box but it doesn’t seem to work as i expect.
The lower cylinder as a 2000mm radius
the upper one is 1000mm
I scaled the upper one centered inserting 2000mm and it get smaller than the original. (!??!?)
I supposed it was a radius/diameter mistake, so I insert 4000mm it get larger but not as the lower cylinder.
What the measure I Insert mean so?
That’s the answer: The diagonal of the scaling rectangle.
That’s quite a mess, 'cause if I’d like to scale a circle I have to build a rectangle around the target circle, calculate the diagonal lenght and then insert that value in the scaling operation.

The answer is no.

and…[quote=“gepponline, post:5, topic:21837”]
That’s the answer: The diagonal of the scaling rectangle.
You just found out that the resulted input is used to get the exact measure along the green grips direction that you use. So you used the corner grips resulting in an exact dimension for the diagonal of the bounding box.

In your case use a side grip and type 4000mm. Resulting in an ellips with one radius of 2000mm
Now use another side grip (for perpendicular direction) and scale again, typing 4000mm. The ellips becomes a circle again with the radius being 2000mm.

Or scaling in one step:
use a corner grip and feed the measurements field by typing 4000mm,4000mm [Enter].
Both values are being used for scaling both directions, resulting in a circle with radius 2000mm.

A 3D bounding box can be scaled in three directions to exact dimensiond by feeding three values in one input.
(as an exercise: try to scale an arbitrary sized cylinder to one with exact diameter and exact height)

p.s. if the field separator between X, Y (and Z) values in your input isn’t responding to a comma then try the semicolon ;

Thank you very ,much!:grinning: