whats the difference beween an extruded arc and a polygon with arc, when they get a fill color ??

[halfcoupler]

anyone knows why this is so ?

[Kevin McAllister]

I'd be curious to know myself. For years arcs behaved the same as your second example. A few versions ago it changed and now arcs extrude to wedge shaped solids. I've often wondered why they revert to a wireframe surface when the fill is set to none. Its like they partly maintained their old behaviour. @Jim Wilson do you know why this is?

 

Kevin

 

[Andy Broomell]

I loathe the fact that arcs extrude into a wedge shape. It's inconsistent with how other non-closed shapes extrude.

[zoomer]

While I would rigorously forbid any kind of "Fill" appearance for any non-closed Objects anyway ...

[halfcoupler]

ok, the rule seems to be that there are 2 differend types of extrudes, (please correct me if I'm wrong):

 

- 1) Extrudes based on non closed 2D-polylines, which apper as "shell-extrusion"

- 2) Extrudes with other (vector-) mathematical definition like circle, oval, rectangle, closed polygons and arc, which appear as "solid-extrusion"

 

The only way to get the "shell-extrusion" from the second type is to convert it to non closed 2D-polygons before extruding

Extract tool is no option for getting extrudes, since it results in a nurbs surface, not in an extrude.