Very Computer

I would like to add an atmospheric haze to a planet which is partially lit.
It seems that glow should be an obvious solution but I can only get it to
glow the entire object, lit or unlit. How do I limit the glow to the lit
areas only?, or should I just try to fake the atmospheric haze with an
additional sphere?

cheers,
grim

[1] try a particle system, so only the tiny translucent particles are lit
[2] try a gaseous plugin like afterburn, or pyrocluster with a transparent
material :O)
[3] use 4-5 spheres with varying intensities and let them be lit by a
raytrace (ick)

hmm...

Ian Skinner
ARQUEBUS ENTERTAINMENT
CANADA
1(705)737-3636
fax1(705)722-6908
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www.arquebus-ent.com ( contruction )  

cheers,
grim
--

http://www.mindspring.com/~grimrepoman/

Quote:> A question for you good people to answer. How do you selectively glow
areas
> of an object in MAX2.0? (without the use of a plug-in like X-Ray).

> I would like to add an atmospheric haze to a planet which is partially
lit.
> It seems that glow should be an obvious solution but I can only get it to
> glow the entire object, lit or unlit. How do I limit the glow to the lit
> areas only?, or should I just try to fake the atmospheric haze with an
> additional sphere?

fiddle with the radial transpareny settings in the glow vpx. This lets
you glow half the sphere or whatever.

Next up I tried the radial size parameters and could get the glow to appear
on the top (lit) surface of the planet. However, this made the planet look
like it was falling since the glow had a noticeable peak at the centre top
edge of the planet.

Next I tried the bright settings. This also allowed me to selectively glow
the upper edge, but made the planet itself far too bright.

Any other suggestions, or will this boboland material thingy do the trick? I
would like to create a glow on the planet that would change as the surface
area lit changes. So as the planet comes into more light, more atmosphere is
visible. This way I could more realistically animate the sun coming up over
a planet.

Cool problem. ! :)

I looked into it and have found one solution, here is what I did:

I used the plug-in "Dust" from Blur S. at
http://www.trinity3d.com/downmax2.html#d

Installed it and did the following:

Used a Sphere gismo (atmospheric apparatus) and placed it around a Mesh Sphere
(earth). Setting how far out the atmosphere would be.

Then in the Environmental dialog I selected Dust Devil V2.05

I left most of the settings to default and only changed the following:

Compositing : Combust Style (or any other you see fit)

Noise Levels 0.0 (smooth surface)

Density : 40.0

Max samples: 80 + (removes graphics quirks, but adds ro rendering time)

Out Self Illim: 0.05 (creates a thin rim around the planet where there are no
light)

Picked a Omni Light under Illumination / Extended Characteristics (you may have
to increase the contrast and Multiplier in the the lights setting to get the
desired result)

You can add Shadows and self intersecting shadow etc. (this adds to rendering
speed, but looks better)
[Image][Image]
[Image][Image]

Good luck

TatA

You can try this way...

Create two spheres, one slightly larger (the atmosphere)

Flip the normals of the atmosphere

Create two lights - one lighting the earth and another lighting the atmosphere which are opposite each other.

Exclude the earth from the atmos light and vice versa.

Create a dummy at the centre of the earth and link the lights to the dummy.

Use Blur's sidefade material in the opacity slot of the atmos material (You'll need to tweak the settings), and turn shininess off.

That's it - works pretty well and doesn't crawl like atmospheric effects do.

Hope this helps

Steve Green