David D wrote:
> I am interested in 3D modeling and POVRay in particular because of the strength
> of the Scene Decription Language.  

Yup.


I am not an artist by any stretch of the
> imagination 

It's a new beginning



and that's where I go wrong with mesh-based modeling programs like
> Blender -- you quickly get to a step where you are required to tweak your
> creation visually, whereas with the SDL if you can define it mathematically
> then you are golden.  

True, but not absolutely true.  For regular geometric shapes these 
programs do accept numerical parameters but perhaps have differing 
levels of support for changing the parameters or producing them 
algorithmically.


I can picture what I want in my head, but representing
> that as a mesh is tough.  I have seen some nice pictures on IRTC that were
> created with nothing but SDL.

And that is one very good source.  In the early days, contestants posted 
their SDL and sifting through that stuff was how many of us learned.

Also there are some GUI modellers supporting POV style primitimes and 
exporting to POV, such as Moray or POV Lab.  You might consider using 
such a tool to play with possibilities and try and better understand 
volumetric shapes.  I am not suggesting it be a magic-bullet, final 
solution, just one ancilliary way to learn.  I don't know of any tuts 
for using these tools in the 'here's how to model a flower' sort of 
vein, though.  If there were, it would probably be the thing you want. 
(The program 'Poser' has a feature where its models can be viewed a 
block-shaped volumes, btw.)


> 
> I have created several smaller scenes with simple unions, differences, etc --
> but my question is for a more complicated model, are there any texts available
> that train you to see in real-world objects the spheres, partial torii,
> cylinder intersected with a plane unioned with a lathed spline, etc?  As an
> easy real-world example I'll use a book case -- I can take a rectangular solid
> box and then remove several smaller boxes to make shelves.  That one is pretty
> easy to see, but what about more complicated and irregular objects like a bird
> or a space shuttle?

Can't think of anything off the top of my head.  Modelling in pure 
primitives is a niche interest. (First of all, most hobbiest programs 
supporting primitives really implemented them as mesh, so up and down 
the scale, mesh has always been the thing. The interest in true 
mathematical primitives is very limited.)

I do recall a book devoted to modelling insects, and showed how to 
derive the complex shape from a set of geometric volumes. This book was 
kind of analogous to the sort of hobbiest, 'how to draw' books that you 
may have in mind.  These how to draw books, aimed at the amateur market, 
would illustrate some process of stepping through the visualizing of a 
complex organic structure, such as a bird or horse, by first roughing 
out the shape as basic geometric volumes.  This idea of course has its 
precursor throughout the history of art.  But that is a whole other 
diversion, except to point out that you are not wrong in hoping to find 
some sort of standard codex for breaking doen complex structures into 
simpler volumes.  It is just that in the digital world at large, this is 
usually played out as mesh modelling.


Of course mesh modelling, and this is particularily important to its 
detractors, is a bit like drawing in that it deals with surfaces of 
shapes, complex shapes to be sure, but just the surface.  One whole 
appeal to virtual modelling is the potential for constructing complex 
shapes by piecing togther the internal or component structure that 
results in the outward complexity.  This is more often the purview of 
the primitives modeler. While this also has its analogue in the history 
of art, (such as George Stubbs anatomizing horses,) it dovetails nicely 
with design fields like engineering and architecture or scientific 
fields like biology and chemistry.




> 
> I suppose this is more of a general art question with applications to either
> sculpting in clay or computer modeling -- but I have searched a few Barnes and
> Nobles, Amazon, and several resources on the internet but cannot seem to track
> down what I'm looking for, or even how to accurately phrase the question to
> make a meaningful Google search.
> 

Visualizing complex volumes as a sequence of simpler volumes is one 
aspect.  But the world of CSG is also much about clever ways to use 
'differences' 'intersections' and 'scaling' of shapes to produce complex 
surfaces.  I do not know of any book treating this.  There have been 
over time various attempts to regularize these tecniques into macros and 
include files.  You should search through the resources and ng's here 
(esp the binaries postings) for these efforts, not only to use, but to 
examine and learn methods.

Finally, breaking down complexity, or clever techniques for welding 
seams, can still only go so far.  In the end mathematical primities will 
impose a mathematical look.  The most exciting visual artists  transform 
the look imposed by their materials into a comvincing illusion or 
personal statement through the intagible quality described by the word 
'style'.  In part it involves somehow harnessing the most intractable 
qualities of the materials used rather than overcoming them.  There are 
many clever ways to do this and many more to be discovered.  Often it 
involves creating a very complete and analogue sense of reality withing 
the parameters of the material.  Recently, for instance, there have been 
some great postings here from people working within the 'childhood 
world' of Lego models.

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