Planet Ring

Started by CCC, February 20, 2010, 06:29:02 pm

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CCC

I was quickly working on doing a ring without using any image imports. It works for sure but it lacks tiny ringlets of color and opacity changes which i can not figure out how to do so here is the file to modify with and hopefully someone can figure it out. Also why is there no shadow being projected from the ring over the planet?

Henry Blewer

You may be able to stretch power fractals into a ring using functions, but I do not know how.
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

CCC

I just applied power fractals to the disk object maker but when i use the opacity settings inside of the default shader with various power fractals it is either completely transparent or completely solid.

Henry Blewer

You might have to use image maps... I think there is a planetary ring scene over at NWDA. You may get some ideas from that.
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

CCC

I did use an image map already and the same results. I'd like to try and stick with everything internally as much as possible.

TheBlackHole

Try making an .obj with your  intended ring shape.
They just issued a tornado warning and said to stay away from windows. Does that mean I can't use my computer?

CCC

That should not change on weather or not a projected shadow over the planet is there or not. Perhaps my sun angle is off. Still, my primary concern is transparency and ringlets.

TheBlackHole

I wasn't talking about trying it to get your shadow. I meant to get ringlets and transparency.
They just issued a tornado warning and said to stay away from windows. Does that mean I can't use my computer?

CCC

Still should make any difference anyways. Shaders are shaders.

CCC

Anyways i tried stretching the noise along every axis is could mix and playing with various means of transparency using every shader i could use and nothing changes so it looks like this ring test is pointless because without that level of realism why bother.

dandelO

Brainwave... Back in a bit, if it works I'll be back in here shortly...

matrix2003

Sending karma to Dandel0's brainwave.  Who's with me!   hmmmmmmmmmmmmmmmmmmmmm.
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-MATRIX2003-      ·DHV·  ....·´¯`*
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CCC

Even with Caffeine i can't get this but dandelO to the rescue.    ;D

dandelO

It's broken. See these quick renders.

[attachimg=#]
[attachimg=#]

The far side of each ring doesn't seem to render, no matter what angle the light is coming from. These are clouds, and brightly coloured just for easy editing as I test this out, each ring could use its own independent fractal for variation, here I just used one fractal.

I'll post the clip file of the planet, too. I can't work out how to render the rings on the opposite side of the planet from the camera, maybe someone can find a remedy quicker.

The secret is in the cloud fractal shader's blending shader node. You can't exceed the limits of the 'spacing' value in the 'Main contour' field of inputs and you must use 'Y for altitude' and match that in relation to the ringed planet's altitude. For testing this out this is a tiny planet of 20m radius, its 'Y' value in the scene is 30m. So, I need a 'base altitude' in the contour shader of 10m to bring the rings into the centre, instead of at the top and bottom of the planet.

The contour shader is set to twice the planet radius. If you breach the 'spacing' of the contours with the 'thickness' of the contour shader, it'll also apply rings at the top and bottom of the planet too. Just use careful adjustments to keep it all in line with the planet's radius.

Just tidying it up, maybe someone can fix the rendering issue. I've tried ray tracing the clouds, it doesn't help it. All the ring layers also use no acceleration and have ray traced shadows checked to get the planet to cast onto them, I can't figure out the missing areas...


dandelO

March 02, 2010, 09:06:50 pm #14 Last Edit: March 02, 2010, 09:28:31 pm by dandelO
* You can also change each ring layer's distance, make them wider in size or even intersect each other in each cloud's altitude and depth settings to make them appear inside each other. Ring size and distance is also relative to planet radius.

This clipfile planet will appear at XYZ = 0m,30m,0m.(Thirty metres above the bottom corner of the main heightfield shader in a default scene). It's only for testing on, that's why it's so small. This should work at any scale as long as you use relative values for the contour shader and the planet's 'Y' value.

[attachimg=#]

I just wish it worked fully without these missing parts in a render. It's a nightmare when something doesn't work as I think it should! :D
Is it a bug or am I doing something wrong? I usually do. :-[

EDIT: I should've said: To see what the contour shader is actually doing while editing its spacing and thickness, just plug it into the planet 'surface shader' input instead of the power fractal. You'll then have an idea where the rings will appear.

* Also, need to work on rotating them. These ones won't tilt.