Foam - Foam Texture

Each foam particle can contribute a texture, similar to a wetmap where the fluid particles leave marks on a black canvas. There you also have several parameters to control dissipation and diffusion effects to make the particle marks vanish over time. With foam maps you have these options as well.

Calculate texture

This mode allows you to store a grayscale texture map for each simulated frame. Calculating a texture map is a computationally intensive process and should only be activated when you really need it. Activating this feature is only one half of the process. To store the maps this feature has to be activated under "Export Central". You can choose between five different image formats: BMP, JPG, PNG, TGA and TIF. If the selected format is capable of 16-bit (e.g. TIF), the texture will be saved as 16-bit grayscale, otherwise the 8-bit mode is used.

Foam maps and textures made from RealFlow particles often require a certain amount of post-work with appropriate image processing programs. Map sequences can also become assembled to video files, showing the motion of a foam layer.

@ source

You can choose whether you want to calculate the foam textures from foam or splash particles.

@ resolution

In RealFlow texture maps are always square, regardless of their origin. Therefore this concept is also valid for foam maps. Whatever shape your grid fluid domain might have, the resulting texture map shares equal side lengths. For that reason there is only one value available. By default a foam map has a size of 256 x 256 pixel, but in most cases that is not enough. Very large texture maps might slow down RealFlow’s simulation process, because it takes some time to create and store them.

@ diffusion

Real foam shows areas of high and low concentration. Between these areas, foam flows in and out creating the typical patterns. “@ diffusion” simulates this process and in technical terms it is the rate per area unit at which foam moves between these zones.

@ dissipation

Under real conditions foam disappears depending on the surrounding conditions, like weather, wave height, or pollution. With “@ dissipation” it is possible to make foam last longer or disappear very fast to mimic these environmental influences. Higher values will keep the foam longer.

@uvw mapping

This parameter is only available when “Calculate texture” has been set to “Yes”. There are three options for creating the maps: each standard particle carries its own set of UV coordinates. “UV particle” can read these coordinates and transfer them into a texture map. In “Top projection” mode the texture coordinates are taken from a simple plain top projection. Finally, there is "Top projection (Average velocity)". Here, the texture coordinates are again taken from a top projection, but in this case the projection plane is moving with the average velocity of the fluid.

Create texture from image...

Similar to “Create particles from image...” this button again opens the file browser dialogue to load an image. This picture will be projected on the fluid surface in XZ direction. When you work with this function, only the red channel from RGB images is used. The pixel values represent the foam’s density.