Dome on top of cylinder

I am trying to put a dome on top of a cylinder.

I draw a vertical (blue axis) line the height I want the “bump”.
I use arc tool that takes both ends and the mid high point to draw an arc.
I close one side of the arc from the base of the centre to the end.
I get a face
I delete the other side of the arc.
I choose the “follow me” tool.
I click on the face.
I choose the circle edge and follow it around and only parts of the arc “follow me”.

Once I am at the end I end up with large pieces of the dome missing and I can look down into the cylinder.

Where have I gone wrong.

I am a total noob and am using the free version of Sketchup.

Click on the circle first. Then activate Follow Me and finally click on the face.

If you are getting a hole in the dome, scale the model up by a factor of 10 or 100 and try again. SketchUp won’t make very short edge segments and without the edge segments, you can’t have faces. Those short segments can exist so you can scale back down after creating the dome. Or use the “Dave Method”. Search the forum for that. Box did a nice animation that shows how it works.

do you mean click on the face or the perimeter of the circle?

I have to click each segment to get the perimeter but as soon as I click the follow me tool the selection goes away anyway.

Sample screen shot of what I am getting.

Select the path (perimeter, if you like) first, get the Follow Me tool, and click on the profile. Yes, the selection appears to go away but that’s not a problem.

You can select the edges of the path with a selection fence dragging it from left to right. You might need to orbit the camera a bit to make it easier to select only the edges you want.

How did you create the cylinder? Why is the perimeter exploded into segments?

Again, work at a larger scale to avoid the missing faces.

In this instance you can select the actual face of the circle rather than the perimeter. But as Dave points out, scale is important.


@DaveR and @Box, thanks for the guides, x10 scale got me there.

I don’t know why my cylinder has so many segments. I drew a circle and did a pull on it.

I may have increased the # of segments after watching some videos on drawing cylinders.

Me cylinder does not look as “smooth” as the sample from @Box, why?

As I said, I am a total noob at 3D Design, sorry for taking up your time.

The lines on the side of your cylinder come from the vertices at the ends of the segments that made up the original circle. Your circle ended upexploded before the Push/Pull operation. Box’s didn’t. You can select those edges and use Soften/Smooth to create the look Box got.

As for the time, no worries. WE are here to answer questions like yours.

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Do I only select the edges or edges and faces on the column and do I soften and smooth, soften or smooth and where exactly do I do that?


Probably the easiest is to triple click on the cylinder with the Select tool. This will select all attached geometry. Then right click and choose Soften/Smooth which should open the Soften Edges window. Drag the slider a little to soften only the edges you want. You can most likely slide it to the right and back to 30°.

You can also hold Ctrl while clicking over the edges to be softened with the Eraser tool.

Lots of other geometry attached to this cylinder now so triple click didn’t work.

I selected all the edges and right clicked but didn’t get a soften/smooth option.

Any other thoughts?

Why not. It doesn’t matter that there lots of other geometry attached.

Did you right click on a selected edge? If not, you wouldn’t get Soften/Smooth.

Did you use the Eraser with Ctrl like I also suggested?

@DaveR, Using Ctrl and eraser turns the edge from a full line to a dotted line, is that correct?

No. Dashed. That is a Softened/Smoothed edge which won’t show at all if Hidden Geometry is turned off.

@DaveR, you are right, dashed not dotted, so that is correct?

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Yes. When you turn off Hidden Geometry (View menu) those edges not be visible.

One thing to note here is that Box created a face on top of the cylinder and used the face as the follow me path. As such you don’t need to pick all those edges (lines) along the circle’s edge.

To make the face on top of the cylinder, simply draw a line across the circle from one side to the other. Erase the line after the face has been created.

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Better still, just trace one segment of the circle with the pencil, then there is nothing to delete.


Agreed…certainly another option.

My only point is that, like in life, there are many paths to the same
conclusion. Some, granted can take a bit more time, but all will lead to a
similar understanding.
I really don’t want to debate anything here. I simply always note what
might have been left out to make things more clear to the new student.
I do a lot of live SU seminars and find that, being the more experienced
one leads me often to skip over what seems to me quite obvious until it is
pointed out by a student.

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