Have any one tried Sheer-and-Wrap: a tech for 3D volume rendering?
Qinghuai
> Aditya,
>
> The conventional approach to volume rendering has been ray rasting. In
> ray casting, each point on a ray projected from the eye position through
> the volume is processed sequentially. In this technique,
>
> 1. The colors, opacity and shading of a volume are sampled, filtered and
> accumulated at a point on a ray specific distance from eye position.
>
> 2. The distane is incrmented along the ray, and the same colors, opacity
> and shading computations are repeated by the CPU.
>
> 3. When the traversal finally moves beyond the viewing frustum, the
> point of computation moves to the next ray near the eye point.
>
> Java3D will be of no use if you decide to use conventional ray casting
> procedure. However, you can use Java 3D to implement Volume Slicing.
>
> In volume slicing, all points on a plane orthogonal to the line of sight
> are computed sequentially in the texture mapping hardware. In this
> technique:
>
> 1. The volume is sampled in the surfaces orthogonal to the viewing
> direction.
> 2. After the points along one plane on all the rays intersecting the
> volume are processed, the distance is incremented and the processing
> occurs again for all points on all the rays in the new plane.
>
> 3. Processing the points continues until the place of points moves
> beyond the viewing frustum, at which point the processing terminates.
>
> The advantages of volume slicing technique over ray casting are:
>
> 1. Volume slicing is faster than ray casting, because computations are
> performed by the dedicated texture mapping hardware, whereas ray casting
> computations are performed on the CPU.
>
> 2. Volume slicing reduces the volume to a series of texture-mapped,
> semi-transparent polygons. These polygons are no way special and can be
> merged with any other polygonal data base handed to any common 3D
> Graphics API (for example Java3D or Inventor etc) for drawing. Hence you
> can mix and match surface and volume rendering freely under the volume
> slicing scheme.
>
> SGI has already implemented Volume Slicing technique on top of OpenGL
> and calls it OpenGL volumizer. Volumizer is a C++ based api and is
> currently available for only IRIX platform.
>
> I am sure Java3D can also be used to develop an API for volume slicing
> puprose but by no means its a trivial task.
>
> Hope this information helps.
>
> Rahul Choudhury
> G.E. Medical Systems.
>
> ----------
> From: Aditya Datta[SMTP:[EMAIL PROTECTED]]
> Sent: Friday, May 21, 1999 3:21 AM
> To: Java 3D Mailingslist
> Subject: [java3d] Volume Render
=====================================================================
To subscribe/unsubscribe, send mail to [EMAIL PROTECTED]
Java 3D Home Page: http://java.sun.com/products/java-media/3D/
