pls clarify my doubts

hi all,
and sorry to interrupt you like this.!!!
actually i have lot of doubts and lot of confusion about the role of
solid modeling kernel inside a solid modeler.
i am cad cam student and worked on packages like solidworks, ideas and
cadmax.
and also i have a little bit of programming background(half knowledge
is dangerous indeed!!!) and that's why this confusion.
could someone please tell me what is the exact role of a kernel??(i
also heard of an operating system kernel)
and what is the difference between apis like java3d, opengl and
kernels like parasolid and acis?? or is opengl also a kernel???
also if possible i want to see some sample kernel code..where can i
get it from...
i will be very grateful to you if you manage to clear my confusion and
doubts..
and also i am interested in knowing the history about the kernel
phenomenon..how come it started..which was the first kernel
developed..etc ..
thank you and have a nice day....
regards,
yogesh

 

yogesh ...

The word 'kernel' is used to describe software that is enclosed, or wrapped,
inside other software. The analogy is drawn from a nut, which has a shell
that encloses the kernel. The kernel contains all the goodness, and is
usually edible; the shell is a protective wrapping.

The kernel of an operating system is vital software that is protected by a
shell. As a computer user, you never see the kernel: you can interact with
it only through some other means (such as the 'ls' and other commands in
Unix, or Windows Explorer).

As a programmer it is possible that you can make calls to the kernel using
its published API.

These are graphics APIs that let you draw 2D and 3D objects on a canvas.
They are unrelated to the operating system kernel.

Look at it this way: if the operating system kernel dies, the computer
crashes; if a graphics API dies, you see a messed-up screen but you can kill
the process and start again.

They are kernels in the sense that they are hidden inside a shell, so the
user can't see them. Actually, they are libraries: as a programmer, you can
use the pubished API to use them.

Most kernel software is not only hidden from users, it's hidden from
programmers. Microsoft, for example, certainly is not going to let you see
the kernel code of Windows. You must also be more specific: what do you
want to achieve?

 

You're too clever by half Jon
Superb explanation, as ever

--

Regards
Dave Preston


www.cadesignservices.co.uk

 

(yogesh) wrote in

The other response here pretty much summed it up but in the spirit of a
public forum let me spew my thoughts:

The word "kernel" pretty much refers to the core of an OS that runs all
the low-level stuff. ACIS and Parasolid are better descibed as
"engines" that software developers can mount into their own applications
so they can offer advanced 3D capabilities without developing their own
libraries (a very time-consuming task). The companies that develop these
libraries license them out for a fee. If you're familiar with games
you'll probably know that id Software licensed their Quake engine to
numerous game developers so they could write cool 3D games without
reinventing the amazing wheel that John Carmack created. This is the
same concept.

OpenGL, DirectX, and Java3D (?, that's new to me) are graphical libraries
that insert a layer of abstraction between the software (CAD, games,
etc.) and the hardware. When a software developer writes an application
that supports OpenGL (or whatever), it should run on every video card
that has drivers written to support OpenGL (or whatever).

As far as examples of code are concerned, I'm not sure how this stacks up
to ACIS or Parasolid but:

http://www.opencascade.org/about/whatis.html

That's actually a very interesting question. I don't know the answer,
unfortunately.

 

i want to see some sample kernel code..where can i get it from...

The solid kernel source codes (all of them) are available in SMLIB solid kernel.
But they are definitely NOT for free.

The trial license of ACIS (90 days) is indeed free and includes a lot (but not all)
kernel sources.

HTH
/Chris Z.