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
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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?
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You're too clever by half Jon 8-) Superb explanation, as ever
--
Regards
Dave Preston
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snipped-for-privacy@indiatimes.com (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.
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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.

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