William F Pokorny <ano### [at] anonymousorg> wrote:

> Thanks, Bill, for posting the image_map image with the colors.

Of course.  Many thanks to Philip Laven for making the output of his Mie theory
program available.

> The image is generated 'looking the wrong
> way', for example, but the method has potential for faking effects like
> Glories I think.

Clever way to do it, and yes, that's slow!
Are you using no_image for your shadow-casting object?

I'm also curious why "the wrong way" works, and I can't create a good shadow as
shown by the scattering media documentation page.  Do we not see shadows when
the camera is in line with the light source?

Might need to do an animation of a light source revolving around a ring of
columns . . .


-BW

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On 2/27/25 06:25, Bald Eagle wrote:
> Are you using no_image for your shadow-casting object?

No. It's completely black because there is no direct light or radiosity. 
It's sitting between the camera and the isosurface dust in the wrong way 
configuration; we are seeing the completely shadowed side.

Aside: I am using 'no_shadow' for the dust rings because I don't want 
them to burn time self shadowing.

> I'm also curious why "the wrong way" works, and I can't create a good shadow as
> shown by the scattering media documentation page.  Do we not see shadows when
> the camera is in line with the light source?

Attached is an image flipped the right way around where everything is 
projected onto a white plane (this the original form for the idea). The 
shadowing object is now just behind the camera - as is the light 
projected through dust.

The original idea was to have a colored light source for each ring, and 
to project the image onto some "clouds." This requires 6 light sources 
in my current set up - hence no AA was used in the image attached!

It's enough to show the right way around works too, though need to look 
for other ways to represent the colors (filter in front of the dust 
maybe, to get to one light source and one isosurface dust shape).

Aside 2: I did have to increase my method 3 media samples by about 3x in 
the right-way direction for the media to look smooth. I 'think' because 
the light intensity is spreading more in the right-way-around / truly 
projecting onto something, direction.

Bill P.

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Attachments:
Download 'try02.jpg' (96 KB)

Preview of image 'try02.jpg'