[help-3dldf] Re: Rotations

[Laurence Finston]

 Hans Aberg wrote:

> 
> If one is doing ray tracing on that, I have heard that all surfaces will
> look as though made out of plastic. If one wants surfaces of different
> textures, like wood, ceramics, etc., one supposedly needs to have surface
> elements that are capable of suitably dispersing the light; reflections
> alone should not be enough. Real life objects disperse the lights, which in
> its turn is reflected/dispersed onto other objects. This is what make
> something look real.
> 

What I've read about rendering is starting to come back to me.  Surface hiding
can be done once the data has been rasterized, using a so-called "z-buffer"
for each pixel, containing a value for the depth.  Shading, reflections, and
other light effects must be performed on the 3D-data before projection.  Some
methods convert all surfaces into polygons.  Radiosity is also popular, as
well as ray-tracing.

One possibility I've looked into is using a free renderer rather than
implementing this functionality in 3DLDF itself.  However, while there are a
number of free renderers available, I haven't found one that I think would be
usable.  They are either undocumented or incompletely documented, and some of
them seem to have been developed to a certain point and then abandoned.  Some
seem to have been projects in computer science departments.  Because of these
problems, I decided I'd probably have to implement rendering in 3DLDF itself. 
However, I decided to work on the parser first, which will keep me busy for
awhile yet.  The next step will probably be NURBs, which are a prerequisite
for rendering.

Laurence