Darcy Johnston <djo### [at] inamecomNOSPAM> wrote in article
<38c9d789$1@news.povray.org>...
> I agree with much of Ross' critisisms, but I would add that it seems as
if
> the ambient portion of the windows' texture is too high, so there seems
ot
> be lack of depth to them. But as was already mentioned, I highly doubt I
> could do better. :)
Already fixed!


> One question somewhat off topic: You mentioned some time ago that you
were
> attempting to create a tutorial on using blobs. I was wondering how that
was
> coming along? Any chance we may see it soon? And in the interim, are
there
> any basic hints you could offer to get us started? This is a area of
Povray
> in which I really lack any skill. Also, any insight you could offer on
how
> you do create your textures might also be quite helpfull.

Sure. Lets see, a basic hint......Ok.  To me, blob modeling is a lot like
modeling with clay.  You can add bits, you an scoop huge chunks out, you
can taper to a point.  My personal trick, without which I couldn't make
anything, is what I call Feathering.  
It's taking a blob component, say a sphere, 
sphere {0,1,1 scale <30,5,70> translate -4*y-40*z}

and copying and pasting it several times.  Now go back to the first three
numbers:
sphere {0,1,1.......
sphere {0,1,1.......
sphere {0,1,1.......

Now you decrease the blob power (third number) and increase the radius
(second number).  Leave the first alone.

sphere {0,1,1/2.......
sphere {0,1.2,1/4.......
sphere {0,1.4,1/4.......
Note how the powers of the three components add up to the power of the
sphere you started with.  When rendered with other components this serves
to greatly smooth the lines between components. The downside, however, is
rather messy code.  Still the speed decrease is minimal.  I once had a 10
component blob and a 10000 component blob.  The first only rendered one
second faster than the second!!!!  You must remember to manually bound your
blobs.   To do so put the blob in a union {} statement,
union {
blob{....}
}
and use the same bounds on both.

union {
blob {....
bounded_by {...}
clipped_by {bounded_by}
}
bounded_by {...}
clipped_by {bounded_by}
}

This will seriously speed the render up!
Hope this helps you!

--
H.E. Day

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