Subject: Re: im_sunII
Date: Fri, 13 May 94 17:01:03 
From: cyrus@dialup-1-80.gw.umn.edu (cyrus)

Hi Mark,

> Hi Cyrus, two questions come to mind:

Fire away!

> 1) Can Imagine do 3D glows, or do they have to be 2D tricks like you have
>    used here? Can a glow be applied to an irregular 3D shape independant
>    of camera view location?

Yes and no.  Lens flare (see, I spelled it right!) is supposed to create a
haze around light sources, but doesn't seem to do a very good job at this
stage of the game.  It is very faint even on high settings.
There is a 'Haze' global effect that works only with Bright objects.  The haze
is measured in pixels and efects all objects the same.  For the sun object it
seems that my method is still the best, such as it is.

> 2) I find it very disturbing that the glow fades to black and does not blend
>    in with the grey background. Is it not possible to make a glow fade off
>    transparently? I had thought that the black disk behind it was the culprit,

>    but it appears that is not the case with this image.

Because Imagine doesn't seem to make anything %100 transparent, I set the
radial textures color to 0,0,0 so that it would blend into the black
background disk.  If the texture color is set to that of the desired haze
(255,255,200) then it sometimes becomes obvious where the edge of the disk is
when placed against the black background disk. The corona does not seem to
have this problem, perhapse because it came from the workshop of Mr. Worley
and Co.

It is not very evident in the JPEG, but the disk for the black fade was not
completely transparent at the edges either.

Hope this helps, but please let me know if have any more questions.

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|  Cyrus J. Kalbrener <kalb0003@gold.tc.umn.edu>                   |
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