Re: I Want An Easier, Faster, Better CAD Tool

> You can have a volume enclosed by 
> surfaces but that does not quite 
> make it a solids modeler.

Who said it does?  
And, what in this specific context does "enclosed" mean?
Generally speaking a volume is not defined by surfaces
but by "shells".  It's the "topology" that makes the
difference.

Reread what I wrote.  I indicated that, in my opinion, the ability
to create a shell, define a volume, ..., whatever does not a "solid
modeler" make.  

And let's be specific: what we are talking about is b-rep modelers.  
Some have the ability to create and manipulate (the volume with 
internal void) "solid" (database) objects, some don't.  Some have 
the ability to create and manipulate "disjoint solid" objects, some
don't.

> Kernels deal with the boolean operations 

Rhino does booleans.  That's been stated.

> and keep them updated, among other things.

Ummmmm.... 

> Consider a simple cube with six NURBS faces.
> Now put a hole in it ..... what became of 
> those flat faces? 

They are still there. The surface definition remains unchanged.
Interior trim boundaries were added to shell (or whatever; some 
database entity defining the trimmed surfaces) definitions.
Ref IGES type 144 Index 5 (PTI).

> For one thing, you got "automatic" trimmed

We'll have to agree to disagree that "automatic" does not
a solid modeler or a kernel make.  

Putting that aside though: 
Rhino does booleans, therefore "automatic" trimming.  
Does Rhino have a kernel?
 
> surfaces in the "raw" database ....

Is this getting a little soft around the edges?  
Where else would the definitions be?

> They deal with topology.

Rhino has database entities containing ("deals with") topology 
definitions.  Does it have a kernel?

> http ...

Thanks for the links.  I'll check 'em out.  Wiki I take with
a grain of salt.  I assume, since you made the recommendation,
you're vouching for technical accuracy.

>> Is CAA a kernel?
> <silence>

I confess.  When I entered this phase of the discussion I brought
with me the opinion that "What is a kernel?" resides with "Why is 
there air?"  Your statement took me by surprise.

What are Parasolid, ACIS, Granite but libraries of functions and
sup****ting data structure definitions?  What is the scope of each? 
When do application developers pass user input to library function 
calls and when must they write their own functions and pass the 
results to licensed library functions or simply integrate the 
results in the data set?  Who maintains the history and parametric 
relation****ps?  Varies.  Correct?  

(Now that it's been mentioned; what "kernels" do maintain history 
and parametric relation****ps?  I might lose my nickle but I'd bet 
that is always the application developer's responsibility.)

I see no distinct difference between SchmoCAD passing user input
to an ACIS or Parasolid function and Rhino passing user input to
its 'home grown' function.

If you run across a nice, clean definition of "kernel" ...
maybe I'll buy it, maybe I won't.