"Squashing" a planet

Started by skarlath, May 02, 2018, 01:24:13 AM

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Im working on accurate saturn system however one rather important thing im stuck on is how to squash saturn to its correct equator diameter,
Due to saturns rapid rotation its quite oval in appearance and so its equator radius is 12,000km greater than its polar diameter.
Not sure how to do this though.
Anyone got any ideas?



You could use a planet size Shape shader with edge profile to put negative displacement on the planet.
One shape shader will be enough i think. It displaces kind with symmetry so the underside will be displaced too.
Just not sure about the Atmosphere.


Quote from: Kadri on May 02, 2018, 02:36:08 AM
Just not sure about the Atmosphere.

That's always been my thoughts when changing shapes. Like I wanted to try a super large asteroid years ago but the atmosphere is locked to a sphere it seems.

However... you could possibly simulate expensive and basic atmosphere with v2 clouds, and mess around with the depth modulator and cloud depth.


Or replace planet by sphere, and adjust Y dimension. Atmosphere (if any needed) still being a problem.


Quote from: Dune on May 02, 2018, 03:08:28 AM
Or replace planet by sphere, and adjust Y dimension. Atmosphere (if any needed) still being a problem.

Keep forgetting about the transform parameters on the sphere. Though if a atmosphere/clouds is needed you'd need a hidden planet (render surface unchecked) in the same center/radius.


Yea that seems to work fine for the planet "mesh" but the atmospheres an issue,
also noticing how much terragen hates opacity maps that have any grey in them, get some funky shadows going on.
Might just have to do ring+shadows in vray and comp it


Yes, opacity is still yes or no.


I can't help with squashing the planet, but maybe with the ring:

Quote from: Dune on May 02, 2018, 05:06:55 AM
Yes, opacity is still yes or no.

I think not. Here is something Matt mentioned:

I made a little scene with an additional planet and a ring. To get the right shadow there has to be a second ring for the shadow which has been mentioned before. This one has an image map shader with some grey colors in the opacity slot and is "invisible". The original ring has to be set to not "cast shadows" and has a shader including a glass shader (Ulco's idea!!) to make it semi transparent.
Important: the "Ray detail multiplier" under the Render/ Advanced/Subdivision settings has to be set to 1, otherwise everything behind the ring will be sort of pixelated due to the low quality refraction of the default 0.25.
I'll gather the project and put it into the file sharing section.

Edit: Here it is:


Thanks for your clarification, Hannes, but it's only for shadows, not for 'things'.
QuoteFor now, this only works for shadows, while opacity visible to the camera still works as before: it can only be either 0 or 1 and each pixel will jump to whichever value is closest.

I set up leaves to cast semi-transparent shadows this way for quite some time now, so I hope if it changes to real opacity gradients, it will be a different shader or by check. Or I have to change all materials again  :(


Ah, I see. I thought you were referring to shadows. However your glass shader method helps.


You need much more work on the map for the planet Saturn itself.
Your Saturn looks so unnatural in colors because the colors are so faded.

See this reference picture for instance (Screenshot from the site/link itself below).


Link to the Original Site