William F Pokorny <ano### [at] anonymousorg> wrote:
>
> And attaching one more. It's the previous image, but where I've applied
> 'normal { micro ... }' to the camera too.
>

That is really cool. It looks like the technique could be used as 'sort of' a
substitute for camera blur. And much faster, I assume.

[about the spheres themselves...]
> Most puzzling to me is the upper left sphere where I made the micro
> bump_size large (1.5 I think). It happens once bump_size values get over
> the usual 0.5 limit where normals can start to invert in one or more of
> the x,y,z directions due the perturbation values being so large compared
> to the raw normal values(a).

I didn't know about this inversion problem; I sometimes use a bump_size > 0.5
for the bumps pattern (for example), just to get interesting effects...and in my
camera as well. But I didn't actually stop to notice that the effect of the
normal might not be correct. I guess I need to do some testing.

What is considered a 'raw normal value'? Does it depend on the specific pattern
used?

> The reflections which are there are no longer fuzzy though, which has me
> puzzling. A significant number are pointing away / against the raw
> surface normal sphere rather than mostly being aligned...

I wonder if part of that result might be due to the typical behavior of normals
on a sphere object specifically. It somewhat reminds me of the rather odd
'normal' results obtained when using POV-ray's 'trace' feature, to place objects
on a sphere and to find the surface normal at each point. The objects themselves
are placed correctly-- but the 'handedness' or rotation of each object, based on
the found normal, switch 'alignments' depending on where they are placed on the
sphere. (I'm thinking of the behavior of the Point_At_Trans(...) function when
used as-is to place the traced-on objects, and which 'aligns' them according to
particular quadrants on the sphere surface.)

My own thinking is that a normal at any point on a sphere does not intrinsically
'know' what its handedness should be(?), in order to be consistent over the
entire surface.

This is just a wild guess, of course, and may not have any significance for your
problem.

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