Hi Shaun,

> What determines the number of points on a surface when
> you click show points?

It depends on what technique was used to construct the surface - some surface construction techniques will create a surface that directly inherit the control point structure of the curves that were used to generate them, while some other construction methods may go through a kind of fitting process where the surface is refined until it reaches a particular level of accuracy.


> For example a default sphere shows 86 points. Since there are an
> infinite number of points on a surface I have a feeling MOI shows
> the least number of points possible in order to represent the
> curvature of the surface but still be workable. Is my assumption correct?

Yeah, actually a sphere is a special case - the sphere internally uses the minimum number of points needed to make an exact sphere surface but that does not allow for very good squishing, so when you turn on control points for a sphere it actually shows you the control points for a rebuilt version of the sphere with more points around it. In the future I want to make the number adjustable.

You can actually build a custom sphere with a particular number of points in it right now - to do that you would set up an equator circle and a vertical arc (see attached 3DM file) then use Rebuild on them with the # of points mode to set those curves up with the number of control points you want to have in the final sphere, and then create the custom sphere by using Construct > Revolve > Rail revolve - pick the vertical arc as the profile curve and the equator circle as the rail path, and then pick the revolve axis as the line between the endpoints of the vertical circle and you'll have a sphere with that number of points in it as the result.

If you want to build a flat plane with a particular number of points in it, you can use the Extrude command with the "Set path" option for that, see here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1313.2

- Michael