>
> I can see how blob definition has been written in its simplest form by
> programmers, but for the user it would be much more convenient to input the
> radius of the sphere that would be seen in isolation and the distance the field
> extends beyond this. I know these relate to the actual input parameters by very
> simple arithmetic, which is also is what computers are for.

This will only work for non-interacting blob elements. Whenever two or 
more elements interact, the location of the surface will get pushed away 
from that location. It can be pushed inward or outward depending on the 
strength of each component. Remember that a blob component can have a 
negative strength.

>
> Of course calculating field strengths is going to slow things down, but would it
> be possible to be able to have a fast mode where this left out and the object
> rendered with sharp corners?

The actual rounded "primitives" are really unions of several shapes.
The rounded box use no less that 7 boxes, 12 cylinders and 8 spheres.
The rounded cylinder and cone use 2 cylinders and 2 torus, or a cylinder 
and 2 spheres.
They have the normal, union, mode and the merge mode for use with 
transparent textures where you don't want the inner surfaces to mess up 
things.

>
> I think implementing rounded-object with just planes, cylinders and spheres
> would not be that difficult and would give:
> - an immediate improvement in usability.
I don't think so.

> - Individual radii for planes would enable a significant new repertoire of
> rounded shapes.
A plane is a plane, a simple surface extending to infinity, it have no 
roundness. In POV-Ray, a plane have the geometric definition of a plane: 
An infinite, infinitely thin, surface dividing space in two: above and 
under.

> - Rounded objects as elements would extend this
> - sphere sweep elements would be amazing.

The sphere_sweep primitive exist and is far from trivial, even for 
linear sweeps. Adding blobbing or rounded edges would be absolutely 
nightmarish.
How would you round the edge of an irregular twisting tube and a plane, 
given that the tube can have a variable curvature,  radius and elevation 
over the plane, can travel under the plane or above.
Except in the most trivial cases, you can't make an isosurface 
equivalent of the sphere_sweep.

>
> scott <sco### [at] scottcom> wrote:
>
>> Note that there are two distinct types of "round" being discussed, it's
>> important not to confuse them. The first is the "CAD" type of perfect
>> round that is formed by conceptually rolling a sphere (of radius equal
>> to the round you want) along the edge. The second is this type of
>> "artistic" round that smoothly blends the two shapes, but is not
>> necessarily possible to accurately specify the round radius (or it might
>> not even be constant throughout the round).
>
> My point exactly when I wrote:
>
>>> (The calculation might be faster with cubic; the corners would not be exactly
>>> circular, but would anyone notice or care?)
>
> Maybe we could go further and, with an extra optional parameter, change the
> profile of the rounding from a rounded bevel to a "V" shape?
>
>
>
>

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