Link to build_v1 here:

So David was responsible for building this file for the presentation. And he did his best to try and incorporate the data I gave him for how planetary atmospheres operate, especially gas giants. He chose to create a more proceduralized build for VFX productions over science, as he is more comfortable working on visual effects in the film industry. But feel free to take this build file and modify it as you will.

One cool thing about this build though, is that if you turn on the lens shader/camera distortion options in Houdini you can warp this entire build into a sphere. And it looks pretty cool. You can even parent different parts of the build to the camera to further edit their movement that way.

There are also two static atmospheric layers in this build. These are mostly to make the build look better. But if you want to add minor glows, or light refraction through the planet they work pretty good with that.

There is also a layer of static instanced clouds in the build, which again are there for most detail in the upper atmosphere. You can animate them through the point velocity SOP. Or just turn off the timeshift SOP :).

Considering that gas giants are failed stars, and are mainly made up of gases. We really didn’t need to consider any collisions, or physical ground planes for this simulation. Just the clouds.

These planetary atmospheres are layered similarly to Earths, but are different in their own unique way. They have some of the same names for the levels of their atmosphere as we’d give our own.

One defining feature of a gas giant is that it has a layer of metallic hydrogen. This hydrogen is referred to as metallic, because it is so compressed in the atmosphere that it turns itself into an electrical conductor. If you are creating a build that displays the polar regions of your planet, you might want to consider adding this little detail in. As Northern and Southern Lights have been observed on these planets. In our build we were only doing side views of the planet, so we didn’t add this.

In our build we have three layers of clouds. As Jupiter, our main reference has three main levels of its atmosphere. So you will notice that there are three individual FLIP/rasterization setups.

Another thing that varies per layer/setup, is the opacity of each cloud system. Jupiter’s clouds have some main differences between it’s cloud systems. These overlaps and distinction between belts and lateral banding is caused by the differences in the opacity of its clouds.

Ammonia concentration is higher in zones, which leads to the appearance of denser clouds of ammonia ice at higher altitudes, which in turn leads to their lighter color. So coloring the clouds was based around this as well. Jupiter and other gas giants are mostly made up of helium and hydrogen. These elements also have their own unique colors. Let’s take Jupiter for example.

It’s atmosphere is very interesting because of its compounded atmospheric pressure. The upper layer of it consists of about 75% hydrogen, 24% helium, and random elements that contain the remaining 1%.

The lower levels of the atmosphere make up about 71% hydrogen, 24% helium, and 5% other elements. These trace elements are methane, H2O, silicon, and ammonia. As well as carbon, and ethane in both gas and liquid form, hydrogen sulfide, neon, oxygen, and sulfur.

When combined together, these elements produce pigments of white, orange, brown and red and blue. The white clouds are from ammonia crystals, the blue tints are from hydrogen, the orange and light pink from helium. As well as even more blue from the methane crystals in the clouds. Also, an important footnote in the color of Jupiter, because the elements in its atmosphere are ionized, the frequency of color in it might change.