I am attempting to model the pallets on a pinwheel clock.
I have created a profile for the pallet ( closed curve as attached). The top edge of the pallet is a very shallow arc centred on the pendulum pivot.
When I try and extrude the closed curve to create the solid pallet, the extrusion process seems to create a chord across the arc, giving a flat face rather than the shallow concave one in the profile.
I have tried redrawing the arc as a curve (also in the attached) , and differencing it from the created solid, but that doesn't work either.
What am I missing please?

I believe that is just artifact of display!

Put 2 as Meshing parameters in Options / View! ;)

Thanks that fixed it.

Hi wisty, that's just a display glitch it's best to just ignore it. It happens when the display mesh didn't generate quite enough triangles in that area.

If you set the mesh angle to a low value like Pilou writes above that will make a denser display mesh but on larger models it will be extremely dense and bog things down so it's usually best to leave that at its default value of 10 degrees.

When you go to export your model you can get rid of those artifacts by increasing the density in the exported mesh by moving the slider towards "More polygons" and also by adding in a distance limiting value in "Divide larger than".

There are various kinds of display glitches that can happen which are a byproduct of it being tuned to be fast.

- Michael