Hi Bard,

> Ok, it must not to use a trimmed surface, the solid/plane it's better.

Yeah I recommend using Draw solid > Plane to build the base surface, it's the best way to get a simple untrimmed plane.


> So, my base surface is a line circle fills by building function "Plane".
> I thought that was not a trimmed surface (a surface cutted, hewed).

No, the Construct > Planar command builds a trimmed surface from the curves you give it, with the underlying plane surface somewhat larger in size than the curves.

All NURBS surfaces are really rectangular in nature, in order to get non-rectangular outlines there can be trimming curves on a surface that mark areas of it as holes or as cut away parts, but there is still a basic rectangular surface underneath those trim curves. But the "rectangle" that I'm talking about with NURBS can be a bendy one, it doesn't only have to be a flat plane and for shapes like a sphere some edges of the rectangle are compressed down to a point in the pole area of the sphere.


> If I draw a Solid/Cylinder & that I keep its base; this will be a solid
> circle or a trimmed surface?
> If I see the points it's a solid surface, is that? If not, it's a trimmed surface.

The caps of a solid cylinder are trimmed surfaces, they're a plane that has a circle as the outer trimming boundary.

Maybe if you could post some kind of drawing of what result you're trying to get it would help me to understand why you are trying to make a disc type surface as the base surface instead of a plane.

Usually a plane is the best base surface - Flow works by going from the rectangular UV space of the base surface mapping into the equivalent UV space of the target surface, and a plane tends to be the easiest thing to deal with the starting UV space since it naturally has a horizontal and vertical U and V directions that are easy to work with.

- Michael