I’m modelling a light fitting, essentially a cylinder, and due to the profile I sketched half of the cross section, then revolved it around an axis to produce the cylindrical body.

One part has a knurled texture, which I now need to apply to the outside surface. To do this, I’m creating semi circles, then copying them rotated around the centre. The problem is that the flat part of the semi circle (actually an arc) doesn’t intersect the surface created through revolve, because that surface isn’t a circle, but appears to be a series of lines/arcs between each radian.

Attachment shows difference between semicircle on the edge of a circle sketch, and the revolved body.

My intention is to repeat the semi circles, then union the bodies to create a single body. This doesn’t work because I end up with non-intersecting geometry. If I use circles to guarantee the intersection, I’d end up with redundant geometry within the combined body.

Revolving a sketch seems to give a much better body than fiddling with lots of extrusions (and can make revisions easier to apply), but it seems odd that the result isn’t perfectly cylindrical.

Can anyone suggest a way around this?