All about PlanetGlow

[DeltaCommando5]

Does anyone know how to use the PlanetGlow diffuse shader??? I've been trying to get it to work and I can't do it. I tried making a planet using the Darksim Planet_Terran plugin, and then adding the PlanetGlow to it. That doesn't work. So I tried making a second, larger sphere and givng it the PlanetGlow but that doesn't work either. How do you do it?!?!?! HELP!!!

[Julian]

First of all, when using any shaders, you have to turn on Plugin Shaders in your render options. Second, the larger sphere has to be less than 95% transparent, otherwise the shader disappears. For the last year, I've been meaning to write a tutorial about using PlanetGlow, but I haven't gotten around to it.

[DeltaCommando5]

Ok, great! Thanks!

[jpappas]

Here is some information from it's creator, Yves Poissant. Note the warning about antialiasing, I think this means MultiPass should be used when trying this. The one time I tried this I was using A-buffer and indeed, the glow rendered as a solid.

 

http://www.ypoart.com/Downloads/Planet-Glow.htm

 

-Jim

[jpappas]

Hi Julian,

 

I've tried using the PlanetGlow Shader on a basic planet. I just want to learn how to start using it. I'm actually seeing a glow so I'm doing better than when I first tried.

 

It looks like there's an inner glow that's really bright and seems to be showing up over the planet model, even though the Glow model is larger than the planet.

 

You get such great results with it, I was hoping you could perhaps look over my steps and make suggestions?

 

Here's how I tried to use it:

 

1. create a 16 cross-section sphere for the planet, and give it a texture

2. create another 16 cross-section sphere for the Glow

3. create a new Material, called it Glow, gave it a Diffuse Color and set it's Diffuse Render Shader to Planet Glow

4. choose colors for the Lower and Higher Altitude Color of Planet Glow in the Glow Material

5. dropped the Glow Material on my Glow model

6. on Glow Model, turned off the Cast Reflections, Cast Shadows, Receive Shadows and Cast Occlusion

7. on Glow Model, set Transparency to 92%

8. put Planet model in CHOR, then put Glow model in CHOR and size it to cover the Planet model (how much larger should the glow model be?)

9. set up Key Light as Sun pointing at Planet

10. in Render Options, turned on Plugin Shaders

 

Well, here's a few pictures to show the results. Again, that inner glow sphere seems to be the problem. These renders were in V14 using MultiPass 1 Pass. I see in Yves' sample project he uses a Spherical Combiner Material with Planet Glow set on two of the Attributes. Do you also use a Combiner with multiple Attributes that use the Shader? I assume this gives a better look?

 

In the second picture I increased the size of the Glow Model.

 

Any help is appreciated!

-Jim

[Julian]

It looks like there's an inner glow that's really bright and seems to be showing up over the planet model, even though the Glow model is larger than the planet.

If the glow shows up over the planet model, the Halo Starts % value is too small. The important thing is to keep track of exactly how much bigger the glow object is compared to the planet object, then set Halo Starts % to the reciprocal of the scaling factor. For example, if you created the glow by scaling up the planet mesh by 120%, then if you set Halo Starts to 83.33%, the glow will touch the surface exactly.

 

BTW, I misremembered in my earlier post -- the maximum value for transparency on a group with PlanetGlow is 99.5%, not 95%. You can set transparency to 99.49% and it'll be OK.

 

Well, here's a few pictures to show the results. Again, that inner glow sphere seems to be the problem. These renders were in V14 using MultiPass 1 Pass. I see in Yves' sample project he uses a Spherical Combiner Material with Planet Glow set on two of the Attributes. Do you also use a Combiner with multiple Attributes that use the Shader? I assume this gives a better look?

I don't think you should use that page on Yves' site as a guide to using the modern PlanetGlow shader, because he created the page back in version 8.5, and PlanetGlow works differently after Yves rewrote it to work in version 12. Putting PlanetGlow inside a material isn't necessary. Also, if you use PlanetGlow on an object with Receive Shadows turned off, the glow will show up even on the nightside of the planet, which isn't strictly realistic and may not be the kind of effect you want. However, if you have Receive Shadows turned on, the planet will cast a hard-edged shadow on the PlanetGlow object. I've discovered a way of softening the transition on PlanetGlow from the dayside to the nightside, but it's pretty complicated to explain: it involves a gradient material with a huge increase in diffuse falloff, whose rotation is linked with an expression to a bone constrained to orient like the sun. This is kind of thing I'd want to write a tutorial for.

[DeltaCommando5]

Ya, you can see in my avatar here that the planet glow is still visible on the dark side.