RealFlow RenderKit 2014 Meshes Particles for Fluid Rendering

The main purpose of RealFlow RenderKit, or RFRK, iscreating meshes directly at render timewithout exporting them to disk. Other tools are included to help render particles effectively, add displacement maps to ocean surfaces, and visualize volumetric data fromOpenVDBfiles. In contrast to the Realflowconnectivity plugins, the RFRK does not support importing or exporting geometry data, meshes or cameras.

Unlike RealFlow itself, the RFRK is not a stand-alone application. It works asmodules from inside 3D applications, which results in some differences between the various platforms. Although all parameters and functionality from RealFlow's meshing engines are also available inside the RFRK, the RFRK does not store the meshes permanently. A mesh file only exists as long as it takes to finish the current frame, but you can load parameters from existing RealFlow meshes with the Import RealFlow XML Scene tool.

When working with particles and meshes it is important tounderstand channels, placeholders that store specific physical data or properties like velocities, temperature, pressure, vorticity and other data. The Cinema 4D plugins, for example, can interpret this information via vertex maps, shaders or XPresso nodes, and connect the channels with Cinema 4D materials to drive transparency and other attributes.

Channels are stored automatically for particles, although standard particles store many more channels thanHybrido particles. Conversely, meshes extract their channel data from the particles, allowing the user to decide which attributes to include with the mesh and finally export, requiring a particular workflow.

When working with channel values, vectors, reals, and integers must be differentiated, which is why some channels have three vertex maps while others have only one tag, and which may allow further calculations. Some channels can also be made visible in RealFlow by choosing attributes and colour contrast.

Rendering Realflow Fluids

TheRealFlow Hybrido Meshrelates to Hybrido, RealFlow's large scale fluid solver used to simulate a fluid's main body of water. It can handle many millions of particles. Secondary elements such as splashes, foam, bubbles or mist are generated with dedicated emitters and treated separately. The Hybrido mesh engine not only processes the particles, but can also use the fluid's ocean statistical spectrum information to add smaller waves and ripples to the fluid's surface. A limited range of channels are supported as well.

RealFlow RK Meshuses the standard particle emitters, also called SPH emitters, to create small or medium-scaled fluids with a high level of detail, making this mesh type the best for fine structures and drops, and to mesh splashes, foam or bubbles from Hybrido simulations. It shares the same parameters as RealFlow's Particle Mesh engine, and supports a wide variety of channels which are read from the associated particle sequence.

Particle rendering

Liquids like foam and spray are normally not meshed, but rendered as particles. The RealFlow RenderKit Particler plugin has functions for rendering very realistic particles. The particle size can be adjusted according to their channels and distance from camera to create view-dependent effects such as speed stretching. TheMultiPointfunctionality will increase the number of particles directly at render time, potentially saving time by allowing you to simulate a scene with fewer particles, after which large amounts of spray or foam are added within the 3D software.

Aside from splashes, foam and bubbles,RFRK_Cloudcreates mist as a fog-like structure representing dispersed drops of fluid. In contrast to other fluid elements, mist is stored in cells of variable density using the → OpenVDB format. Some RFRK versions use existing volumetric shaders, others provide a dedicated shader which can applied to the mist container.

You can generateRFRK_Displacementmaps within RealFlow from RealWave surfaces and Hybrido fluids. Instead of baking an ocean statistical spectrum to a Hybrido mesh, a map is projected onto geometry.

TheImport RealFlow XML Scenetool, mentioned above, makes it possible to load mesh settings directly from RealFlow XML files. This is useful when using mesh parameters from external artists, or from test meshes created inside RealFlow. You can write out a XML file from the entire scene and import it to a 3D application. The tool filters out the contained mesh nodes and recreates them as RFRK containers.

The RealFlow RenderKit is available todownloadfrom the RealFlow download area.www.realflow.com