How do I use the Dimension Tool to show the height of a cylinder

Imaging I draw a circle and pull it up to a given height to make a cylinder… Then I want to use the Dimension Tool to show the cylinder height how do I do it?

As soon as I click on the top or bottom edge, it goes into “Diameter” mode and shows the size of the circle… I can’t seem to find any point I can click on to allow me to show the HEIGHT of the cyclinder

The best I found was a point in the middle of the wall, which gives me 1/2 the height… But I can’t work out how to do the full height…

here is a quick picture to show what i mean.

Infact, this applies to any dimension on a circle… Say I had a washer and wanted to show the distance between the hole and wall… Again, I can’t seem to do that. This is the best I can do

Any ideas… I am using SU2018 by the way.


Temporarily turn on Hidden Geometry and dimension one of the softened edges.

You are awesome… I actually edited my post as there is another similar example too which this tip doesn’t help with.

Draw a temporary line on the surface of the washer. You can erase it after the dimension is added or hide it so it remains in case you edit the size of the washer.

Why are the solutions so obvious, but I don’t think of them? Of course, I get it now…

You have actually been more helpful than you realise… One of the things I do most commonly is to change teh diameter of a cylinder… Normally, I do this by grabbing the cardinal line (is that the right word)? But often I can’t find it and I end up spinning the model around looking for the blue dahed line

I just realised that if I turn on “hidden geometry” I can ‘move’ any of the lines to achieve what I want… This is one thing thats bugged me since I started using Sketchup… I am sure there are other ways to do what I want… But this is the only way I know… And now with Hidden Geometry this is going to get a whole lot easier.

So whilst I am sorry to waste your time with an obvious quesiton, you have been a MASSIVE help!

Thanks as always.



Actually., I was wrong… Grabbing a line does allow you to change the radius, but it makes a mess of the geometry…

So now I am going to have to ask a quesiton about “cardinal lines”… Why can’t I always find it?

I just drew a quick washer to play and the blue dotted line appeared when I moved the cursor around the outside wall… Then I added some dimensions and played around… And now there is no sign of the line…

If I wanted to make the radius of the outside wall larger or smaller, the only way I know how is to “move” the cardinal line… But in cases like this where it doesn’t show itself I am never sure what to do.

So this begs the question

  1. Why does the line not show? And how to make it appear?
  2. What other methods are there to make the diameter of a cylinder an exact amount bigger/smaller?

You could edit the radius in Entity Info.

So I would have to do the top and bottom radius? That would work… I could live with that.

What am I not getting about Cardinal lines… Whilst waiting for your reply I tried agian… I created a washer… And I had the blue dashes at 4 points around the ciricle… I then played around a bit and then changed the size using Entity Info as you suggested… And now, I have no cardinal lines…

Is there any way to force them to appear? A quick key or menu option that I am missing? Why would they be gone now when all I did was resize the outside wall?

I’m in the middle of a robotics meeting so I’ll have to get back to you later but I guess I would be adding dimensions in LO instead of SU so I don’t need to deal with it at all.

Just finished with the robotics meeting.

I don’t know why you are having problems with cardinal edges. I had Hidden Geometry displayed to make it easier to see them but no problem selecting them.

Even after editing the radii of the circles there was no problem going back to the cardinal edges.

One thing I notice in your screen grab of the washer is that the vertices aren’t on axis which could make it more difficult to find the cardinal lines. Best practice its to always drag out the radius of circles on axis.

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Sounds like you may be misunderstanding the cardinals.
Named for the cardinal points of the compass, when drawn on axis with a segment count of a multiple of 4 they will fall at North, South, East and West. The points can be moved individually and in joined pairs.
They will change position as your break a circle, moving to the ends and midpoint of any ‘curve’.
They will disappear totally if the circle or curve is ‘exploded’ which happens with follow me and some other actions.
So as you see in the gif you can change the shape significantly by selecting different points and pairs.

You can also use the scale tool to change the shape and size of objects, the default scale is a percentage but if you add the Unit it will scale to a specific size.


Thanks Both… I don’t know what it is, but sometimes I just can’t find the Cardinal line… Even when I know where it is…

Its there one minute… And then not the next… But weirdly they itsd come back again… Its hard to explaina and even harder to prove… But I have found myself rotating round and round a model, slowly moving the cursor tool trying to find the cardinal points but the blue line never appears… But then I go away and do something else and when I come back its there.

I guess the key to all this is starting drawing right over the centre of the ‘axis’ guide lines.

But what if they object is drawn without the RGB (axis) reference lines, how do you find the cardinal points? I guess if your drawing has 1 circle then its good practice to start the drawing in the middle of the axis… But what if the drawing has 2 or more circles… How do you KNOW where the cardinal points (And therefore lines) are?

Are there any tips on how to place an ‘axis’ in the middle of a drawing at the right orientation?

I know this is basic stuiff, so really appreicate you taking the time to help


Drawing on axis doesn’t mean using the origin point, it means pulling the tool out along an axis. When on axis the radius line of the tool is either red, green or blue. When off axis it is black.
on axis
Keeping things on axis not only allows you to know where the cardinals are but it means circles fit together because the segments line up.

At a guess with regard you not finding them at times, I’m going to say you probably have something pre selected. The Move tool only reveals the cardinals when absolutely nothing is selected.
You can see in the gif how the cardinals won’t show when the cylinder is already selected.

All very helpful… I have found a few videos about Cardinal points and Axis, so will study those.

I can entirly break things by drawing something on-axis where i can easily find the cardinal points… And then changing the axis (using the align axis or axis tool)… From then it makes it very difficult to find the cardinal poinst.

in truth, for the type of work I do, I shouldnt’ really be changing the axis… And should just get used to using a single axis and drawing along the line of THAT axis.

Thanks for your help as always… It really is appreciated.