Locomotive dome


I am looking at making a shape similar to the picture below (brass boiler dome), I have been practicing with “follow me”…the challenge with the dome is that the curved skirt is not a uniform radius, it is a tighter radius at the top than at the sides as it blends between the round dome body and the body of the boiler. So a “follow me” for a 2D drawing does not work…can I do a follow me and transition between the radius as I move through 360 degree.

Any ideas how I could approach this…as always many thanks in advance.

Does this look like it would do the job?

Modeled in meters to prevent tiny face issues.

I drew a cylinder the diameter of the base (I’m assuming in plan view the bottom rim of the dome is circular) and intersected it with a cylinder for the steam jacket. Then I drew profiles for the side and front of the dome base.

Fredo6’s Curviloft made quick work of skinning the quadrant of the dome base. I copied the resulting group and flipped it accordingly to make the other four quadrants although I expect you could get away with copying the curves and running Curviloft all around.

The top part of the dome was a simple Follow Me operation.

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If you need to draw it with basic tools (SketchUp Free), then this can be a variant:


Dave - as always thank you…I was holding off loading Fredo6’s plugins but this looks like a good reason to crack on and do this…thank you.

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Wow,thank you…I will try both the method you suggest and the one suggested by Dave…I am in the constant practice stage so both will be good exercises…thank you to you and the forum, every time I ask a question I get absolutely the support I need…

Than you.