If you own UltraCloud, I recommend using the .pdf documentation that comes with it. It is much more convenient, and has a linked table of contents!

Welcome to the UltraCloud documentation! This is where you will find all the information regarding installation and use of UltraCloud, as well as some tips and tricks to get your clouds looking as good as possible. If you have any questions that are not answered here, feel free to ask them on the Superhive Product page! Make sure not to miss the important warnings at the bottom of this doc.

Contents:

How to Install:

Using UltraCloud:

Cloud Base shape generator:

Cloud Generators:

Turbulence:

Cloud Material:

Cloud Planes:

How to export VDBs:

Guide to Modeling Base Shapes:

Some Tips and Warnings:

How to Install:

1. Download the .zip file and unzip it to a location of your choice.

2. Open Blender.

3. Navigate to preferences (Edit>Preferences). Open the Asset Libraries tab.

   
   

1. Click the plus icon to add a new asset library, and choose local. Select the folder in which the .blend file for UltraCloud is located.

1. Choose the import method as Append.

1. You did it! Now you can find the Ultracloud assets in the asset browser of any Blender file with the same Blender version, or add the generators directly as a modifier.

Extra―VDB library installation (this is not necessary, because you can just drag and drop the premade VDBs into Blender, but if you want them in your asset browser, follow these steps):

1. Repeat all the steps from the general installation, but choose the folder where the VDBs are located instead of the folder with the .blend.

Using UltraCloud:

In this section I will cover each part of UltraCloud individually. To best understand use of the product, I recommend reading through this thoroughly, although you may choose to reference it only as needed. In general, you start with a base mesh (handmade or procedurally generated with UltraCloud), and then apply a cloud generator on top of that to convert it to a realistic volumetric cloud.

Cloud Base shape generator:

UltraCloud is designed to allow you to model base shapes by hand for ultimate control, but also features a cloud base shape generator if you don’t need to direct the shape of your cloud as precisely, while still having a lot of control (you can even use a hybrid workflow, letting the generator get you started, and tweaking the cloud manually). This asset only appears in the asset browser. You can find it (usually under unassigned) and simply drag and drop into your scene. Now, if you open the modifiers panel, you will see a set of options. First, there is cloud type, which is set to Cumulus/Cumulonimbus by default.

Cloud type: Cumulus/Cumulonimbus

Seed: this controls the seed of the cloud, basically generating a new cloud shape every time this value is changed. (If you like a seed, but change seeds, returning to that same seed will produce the same base shape)

Base Spread: Cumulonimbus clouds often have a somewhat flatter, spread-out base, with the rest of the cloud sort of mushrooming up from this. This slider controls the spread of this flattened base.

Height: this controls the height of the cloud. It maxes out at 3, because values higher than this cause weird results. If you need a taller cloud, switch to the Towering Cumulonimbus type.

Base Flattening: This controls the amount of flattening of the spread out cloud base.

Cloud type: Towering Cumulonimbus

This has the same controls as the Cumulus/Cumulonimbus type, except that the height can be made higher.

Cloud type: Cumulus Fractus

This cloud type is for generating those wispy, cumulus fractus type clouds. It has only a seed value to tweak.

Cloud type: Cumulus

The Cumulus cloud type has seed and height values, operating the same as in the Cumulus/Cumulonimbus cloud type.

Cloud Generators:

These are the next layer in the system. You add one of these on top of a base shape, and it takes it from a mesh to a realistic cloud. There are 4 types:

Cumulus/Cumulonimbus cloud generator:

Noise Scale: This controls the scale of the various noises used in creating the cloud. Setting this higher will cause the detail on the cloud to be smaller.

Voxel Detail: This value controls how detailed (and thus realistic) your cloud is, although it can cost performance. I recommend leaving this at the default or higher when you are tweaking other settings, and then changing it for the final cloud if needed. Lowering this increases the detail of the cloud, but costs significant processing. I would not recommend ever lowering this below 1. Also, don’t drag this value to change it, which can result in Blender crashing―instead, just double click and type the value you want.

Base Mesh Detail Preservation: Increasing this value can increase the amount of influence the base shape has on the shape of the cloud, at a slight performance cost. The default should be fine in almost all scenarios. You might want to increase this if you are trying to make a cloud in the shape of some other object, like a table or car. 

Material: This assigns a material to your cloud. Ultracloud comes with a specially crafted material that will make your clouds much more realistic than a default principled BSDF or volume scatter, so I recommend always using that.

Cloud Bottom Density Gradient vertical position: In this generator, the density of the cloud fades out at the bottom, creating a more realistic look. This value alters the vertical position of the fade.

Cloud Bottom Density Gradient Influence: This controls the strength of the fade effect. Default should usually be best.

Cloud Bottom Density Gradient Fade: This controls how slowly or quickly the density fades. Lower values=slower fade. Sharper fade (default or higher) usually looks best for Cumulonimbus, while a more gradual fade is better for Cumulus.

Fluffy Cloud Generator:

Settings are the same as the above.

Puffy Cloud Generator:

This generator is for making small, puffy clouds like alto/strato cumulus clouds. It works best with flatter base meshes, such as those generated with the Cumulus Fractus base shape generator.

Shape Smoothing: How much the base shape is smoothed before converting to a cloud. This enables simple cube blockouts to be used as a base shape. Default should usually be fine.

Material: This assigns a material to your cloud. Ultracloud comes with a specially crafted material that will make your clouds much more realistic than a default principled BSDF or volume scatter, so I recommend always using that.

Details Scale: This controls the scale of the details/noise used to generate the cloud. Higher values will decrease the size of features of the cloud.

Voxel Detail: This value controls how detailed (and thus realistic) your cloud is, although it can cost performance. I recommend leaving this at the default or higher when you are tweaking other settings, and then changing it for the final cloud if needed. Lowering this increases the detail of the cloud, but costs significant processing. I would not recommend ever lowering this much below 1. Also, don’t drag this value to change it, which can result in Blender crashing―instead, just double click and type the value you want.

Wispy/Fractus Cloud Generator:

This is for generating wispy, or Fractus, style clouds.

Material: This assigns a material to your cloud. Ultracloud comes with a specially crafted material that will make your clouds much more realistic than a default principled BSDF or volume scatter, so I recommend always using that.

Voxel Detail: This value controls how detailed (and thus realistic) your cloud is, although it can cost performance. I recommend leaving this at the default or higher when you are tweaking other settings, and then changing it for the final cloud if needed. Lowering this increases the detail of the cloud, but costs significant processing. I would not recommend ever lowering this much below 1. Also, don’t drag this value to change it, which can result in Blender crashing―instead, just double click and type the value you want.

Details Scale: This controls the scale of the details/noise used to generate the cloud. Higher values will decrease the size of features of the cloud.

Base Mesh Detail Preservation: Increasing this value can increase the amount of influence the base shape has on the shape of the cloud, at a slight performance cost. The default should be fine in almost all scenarios. You might want to increase this if you are trying to make a cloud in the shape of some other object, like a table or car. 

Turbulence: 

This modifier adds some windy noise to a cloud, breaking it up a bit and adding some detail and randomness. I recommend always adding this to Cumulus or Cumulonimbus clouds.

Strength: This controls the strength of the effect. 

Turbulence Noise Scale: This controls the scale of the noise used to add the windy details. 

Turbulence Noise Detail: This controls the detail of the noise used to add the windy details. Lower values produce softer looks, and higher values produce a more jagged, wind torn look.

Cloud Material:

This material is designed to give the most realistic results. I got the general concept of this shader from the amazing cloud shading tutorials of Samuel Krug (https://www.youtube.com/@samk9632) and Marc Whitelaw (https://www.youtube.com/@breakyourcrayons).

Density: This controls the density of the cloud.

Color: This controls the color of the cloud for unique effects. Keeping this color as white is best for realism. (Please note that, although it might make sense, changing this color to gray is not the way to get a storm cloud look―this should be accomplished by lighting)

Anisotropy (advanced): This is a setting that affects the direction that light scatters through the cloud. It is somewhat technical, and I recommend leaving it at the default.

Volume Bounces: getting this value right is important for replicating the way light moves through clouds when viewed from the dark side. The default value is set to the amount of volume bounces I use when rendering clouds. If you use a different amount, you can set this equal to the number of bounces you use. (volume bounces settings are located in the Cycles render settings)

Cloud Light Effect Strength: This controls the effect of the above setting. Keeping this at the default is recommended for realism, but lowering it slightly can give better looks for storm clouds.

Cloud Planes:

These are 2D planes with shaders on them designed to make adding small, wispy clouds to your scene easier on you and your computer. You can tweak the color or density to achieve your desired result. They can be found in the asset browser.

How to export VDBs:

You can export a cloud as a .VDB file by opening the geometry nodes workspace and selecting the node tree for the modifier you want to bake. Then open the Bake settings of the modifier (Modifiers>Manage>Bake) and change the bake target from packed to disk, then set the file path to the location you want to save your cloud. Then click the bake button on the bake node inside the Geometry Nodes workspace. (Make sure the bake node is set to bake Still instead of Animation)

Guide to Modeling Base Shapes:

I like to model base shapes by hand for the most realistic and controlled results, although I use this mainly for cumulonimbus and cumulus clouds. I start by adding a simple icosphere to the scene, and I duplicate this and move it around to flesh out the shape. It is best to have a Cloud generator in the scene to get a sense of scale. The cloud generators’ detail is related to their size, so if you make a cloud much bigger than the base generator, you could overwhelm your computer. Also, I like to add a flattened base to the clouds I make manually, by scaling down an icosphere on the z axis, then scaling it out on the x and y axis, and duplicating that around. The key to a realistic base shape is a proper blend of different sized shapes, and realism. Also, it is best not to have floating spheres or groups of spheres, as they take away from the realism. I generally model the base shape with relatively large shapes first, then add a single icosphere to the scene. I select the separate parts of the base shape and join them, then add a particle system. I set the frame start and frame and both to 1 (or whatever frame I am on), lower the amount of particles a bit (maybe 400), then go to the render settings for the particle system, set it to render as object, and choose the single icosphere. Next I tweak the scale and scale randomness and particle amount/seed to my liking. Then I open the modifier tab and click the make instances real button. This adds a bunch of icospheres based on the particle system, and they are automatically selected. I hold shift and select the base shape, and Ctrl+J to join them. Then I remove the particle system. That way I can add some smaller, billowy details without doing it all by hand.

Some Tips and Warnings:

• The amount of voxels in a cloud, and thus the amount of detail and performance load, are relative to its size in the scene. Scaling up clouds (If you apply the scale) can overload your computer. The base shape generator and cloud generators are designed to function at a smaller scale to make them more manageable. For maximum realism, it might be best to scale up your cloud to an accurate size, but DON’T DO THIS UNTIL YOUR CLOUD IS BAKED!!! 

• You can bake a cloud (meaning your computer will stop having to process it), by opening the geometry nodes workspace and selecting the node tree for the modifier you want to bake and clicking the bake button on the bake node. (Make sure the bake node is set to bake Still instead of Animation) Baking modifiers can be very useful if you have, for example, a Cumulus/Cumulonimbus generator all set up and want to add a Turbulence modifier. Baking the generator will reduce the load on your computer and make tweaking the Turbulence modifier more responsive.