Digital Art Zone

I’m a newbie - let’s get that out of the way. I’m running Carrara 8.1 Pro on an iMac OSX Lion. I animated a simple 7 second scene of the camera slowly panning around earth while it rotates. It will be part of a ship flyby.

I created a blue aura that looked the way I wanted in the render preview. Doing the final render, I get a thick over saturated glow around the outer part of the planet that looks nothing like my preview. I messed with it for an hour last night but couldn’t figure it out. Any ideas? Even better - is there a good tutorial for planet glow?

Also, the final render showed the planet rotating but the aura also rotated away leaving the final few seconds with no glow. :(

A screenshot would make it easier to understand, here is a guide that may be what you need:
www.sharecg.com/v/47716/related/3/PDF-Tutorial/A-glow-effect

Aura is a really bad post effect. I never use it because it always looks pixelated and granular, and it doesn’t respect any scene scaling, just pixel width (I think).

If you have any of the plugins that give a fresnel (falloff) effect, you can make another sphere that glows blue (slightly large than your planet and cloud spheres) and set it’s transparency with falloff so you can only see the edges. This will give your planet a “halo”. Without falloff the transparency won’t look very good…

Carrara’s transparency shader has a fresnel setting as of C8…, but I am not familiar enough with it to offer settings suggestions…

I second Holly’s suggestion: use a second sphere with Transparency (not Alpha), slightly larger - not the Aura effect.

I just tried to work with the built in fresnel, but I do not think it can be purposed for this…

See the 2 Faking Atmosphere videos at:

http://www.markbremmer.com/3Bpages/darkarts.html#p7GPc1_5

One is a tutorial and the other video shows you a rendered scene using the technique.

Also are you just using one sphere with a texture one it for the planet or multiple sphere with your ground terrain on one and your clouds on a slight larger one surrounding the ground terrain one.

I rarely disagree with Holly or Fenric, but I’ll do it here, with some caveats. Here’s a sample using the aura for an atmosphere effect that I did awhile ago:
http://www.youtube.com/watch?v=c2XfqXVtGAQ&feature=share&list=UU6wB1FKPN4DWpuoVsQY2o8Q

The video uses three spheres. One for the planet surface, one for the cloud layer and one for the “atmosphere.” For the atmosphere I used a medium blue shader in the color channel, a numerical slider in the alpha channel set to 1%, and a light blue color in the glow channel. I’ll include a screen shots of the shader and the editor for the aura as I’m getting tired of typing.

Here’s the caveats: I wouldn’t use the noise functions in the editor and since it’s a post effect other post effects won’t play nice with it sometimes. It also won’t respect lighting as you can see from the dark side of the planet. I just call it “atmospheric refraction.”

For the animation, I rendered the background layer and the planet separately and composited them in post. Mostly to save render time.

Here’s a quick still render I did with the above settings.

I do see the atmosphere…

Evil, I will attempt this when I get home. I hadn’t thought of using multiple spheres. One of those smack my forehead moments. This forum is great. I appreciate the ideas and your time.

You can also use the “Light sphere” effect, on a bulb, placed at the centre of your planet, although it can be fiddly to set the distance, it’s effect is nice (IMO) and worth the time.

If you don’t want to take the time,. here’s a scene .  https://dl.dropbox.com/u/7907045/planet_fly_in.car

The shaders for the planet and clouds are all procedural, ..but you can obviously replace those with maps or other shaders.

Although aura may not be the best solution for the issue at hand I would not dismiss it as useless. Certainly it has provided just the right touch to images for me in the past. It can certainly be fiddly to tweak, though to a great extent that depends on how you are trying to use it.

I don’t know if my example here shows how nice it can look (the image was rendered for print as a poster and looks much better that way), but it certainly makes extensive usef of Aura…

I Agree with Evil producer and Thoromyr, the glow shouldn’t be dismissed . but I’m also thinking that if Holly and Fenric are suggesting not to use it ,..then there may be some differences with how this effect is working on the different platforms,. and it may be worth posting a couple of Pics,. so we can see if it’s something that’s visibly different on PC and Mac.

My main issue with using the aura in this instance is the fact that it uses Glow in the shader, to power the effect, and it produces an all round light effect.
The Sunlight should cancel out the effect on the part of the planet facing the light.

Also Note:
in the scene I posted above,.. I’ve left a (hidden) plane (vertex grid) which I had set up with a point at (camera) modifier, and it has a radial gradient shader applied to it, to create the same type of fake aura as you see in Mark Bremmer’s tutorial, but using shaders instead of image maps,. this is ok-ish,.. but the effect is all round the planet. ...so I just made it invisible.

No, I don’t think the built-in fresnel will do.  Go get sparrowhawke’s free falloff shader and use that.

http://www.sparrowhawke3d.com/Sparrowhawke3DPlugins.html

I didn’t mean to suggest that you should ignore Aura forever for everything, just that I don’t think it gives a particularly realistic atmospheric shell. 

http://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57723/globe_east_2048.jpg

I was trying to get something useable without a plugin… Carrara’s built in fresnel works to make the center of the refractive object show it’s effect. For a good atmosphere glow you’d want the edges to show more effect….

I tried using some other shader tricks: light scattering, translucency…. Some things might work in certain circumstances, but Glow and a fresnel filter is easiest.

If you are feeling confidant you could use a SPLAT painted with a glowing ring. Parent the SPLAT to your Earth/Clouds group, and make the group point at the camera. Totally fake, but totally controllable…

3DAGE - 02 November 2012 06:49 AM

so we can see if it’s something that’s visibly different on PC and Mac.

I could post some, but all you’d find is that they are identical. I’m almost 100% OS X now (still run Carrara in Wine on linux occasionally), but I’ve done a fair amount of crossplatform rendering. There may be some area where they do differ, but I’ve never encountered it.

3DAGE - 02 November 2012 06:49 AM

My main issue with using the aura in this instance is the fact that it uses Glow in the shader, to power the effect, and it produces an all round light effect.

It certainly isn’t the right choice in all situations.