Thread Subject:

Shape that have close form and more varying than ellipse

Dear all,

 I want to find a shape has close form, (Like circle) but need to be varying more than ellipse. Please help

Thanks

"Marco Wu" wrote in message <j6f3dh$sgf$1@newscl01ah.mathworks.com>...
> Dear all,
>
> I want to find a shape has close form, (Like circle) but need to be varying more than ellipse. Please help

doc regionprops

Sorry for making misleading. I need to create a special shape pulley; and want to have more varying than just an ellipse. I need something that has a close form equation.



"Matt J" wrote in message <j6f3v1$195$1@newscl01ah.mathworks.com>...
> "Marco Wu" wrote in message <j6f3dh$sgf$1@newscl01ah.mathworks.com>...
> > Dear all,
> >
> > I want to find a shape has close form, (Like circle) but need to be varying more than ellipse. Please help
>
> doc regionprops

"Marco Wu" wrote in message <j6f4ur$4m6$1@newscl01ah.mathworks.com>...
> Sorry for making misleading. I need to create a special shape pulley; and want to have more varying than just an ellipse. I need something that has a close form equation.
>
===============


You'll want to give a more complete description of the required properties. Why not a square pulley, for instance? That's not an ellipse.

"Matt J" wrote in message <j6fad7$pii$1@newscl01ah.mathworks.com>...
> "Marco Wu" wrote in message <j6f4ur$4m6$1@newscl01ah.mathworks.com>...
> > Sorry for making misleading. I need to create a special shape pulley; and want to have more varying than just an ellipse. I need something that has a close form equation.
> >
> ===============
>
>
> You'll want to give a more complete description of the required properties. Why not a square pulley, for instance? That's not an ellipse.

Square pulley is not smooth. There are edges.

Ellipse is considered to be the boundary curve of two circles, and it has a general form. I want something that has more variation; and also have general form. For an example, if there exists a general form of the outer boundary of three circles with different radius .

On Oct 4, 12:10 pm, "Marco Wu" <alwaysma...@hotmail.com> wrote:
> Square pulley is not smooth. There are edges.
>
> Ellipse is considered to be the boundary curve of two circles, and it has a general form. I want something that has more variation; and also have general form. For an example, if there exists a general form of the outer boundary of three circles with different radius .
-----------------------------------------------------
Still doesn't make sense. In general, the shape will have some shape
that could look like anything, from a circle to an ellipse to a
square, to a rounded square to a gear, to an asterisk, to some
arbitrary splat-looking object. It may be convex, or have nooks,
crannies, and bays in it's perimeter. You've given no useful criteria
for how to construct a shape. Every shape has Fourier descriptors and
so could be considered as the superposition of other shapes.

On 04.10.11 18:10, Marco Wu wrote:

> Ellipse is considered to be the boundary curve of two circles, and it has a general form. I want something that has more variation; and also have general form. For an example, if there exists a general form of the outer boundary of three circles with different radius .

An Ellipse is not really “the boundary curve of two circles” in any
meaningful way I could think of. But you might be interested in what is
known as metaballs.


Christopher