@jean lemire said:

Hi Peter, hi folks.

@pbacot said:

you don't need to draw all radii to the segments of a circle. just draw a diameter that is broken by a vertex at the center. Move up the center point while pressing the up arrow.

I have difficulties with this. I know the method with two radii or one diameter divided in two (rigth click then choose divide in the context menu) but I cannot see how to draw a diameter that can be broken by a vertex at its center if I don't draw something else to break the diameter.

@pbacot said:

But tell me why: for the second edge you need to shift- erase to keep the cone smooth.

SHIFT-Erase hide an edge.

CTRL-Erase smooth an edge.

So, for a cone made by pulling and endpoint at the junction of 2 radii, these 2 edges must be smoothed.

Smoothing is not the same as hiding. Hiding an edge still shows the angle between the two faces separated by this edge while smoothing softens this angle and blends the two faces into one that gives the appearance of one continuously curved surface.

Just ideas.

Jean, if you try it you'll see that the second line needs to be hidden not smoothed like the first line. You would think they'd both be smoothed. What it has to do with is there is not circle any longer on the bottom. It is two curves. You can put a circle back in.

To break the diameter at the center, draw the radii separately from the center.

Peter