HYM - Boundaries

Owned by thomas (Unlicensed)
Last updated: 05 Jun, 2014
4 min read

With the parameters and options in this panel you will be able to crop the Hybrido mesh, remove unwanted parts, and extend the mesh to create the impression of a huge ocean surface. Changes are added automatically and there is live optional feedback in the viewport: if the interactive meshing mode is disabled please go the the "Mesh" shelf and click on the "Mesh interactive" button. In the first step, you have to go the desired frame and build a single mesh with

Mesh node > right-click > Build mesh

or the appropriate button in the "Mesh" shelf. Now, all changes within the "Boundaries" panel will be applied automatically and you do not have to rebuild the mesh manually. Once you are finished with your adjustments, simply recreate the mesh again to bake the settings to the current mesh. Finally, you can mesh the entire sequence. The parameters from the "Displacement", "Filters", and "Optimization" panels also support interactive meshing. For more information, please click here.

 

 

 

Open boundaries

When you take a look at the Hybrido domain's viewport representation you will see a square with four boxes – here only the square is interesting: it represents the projection plane for the fluid's displacement and image export (displacement, vorticity, velocity). When “Open boundaries” is set to “Yes”, the mesh polygons in the outer areas of the projection plane will be cut away. The plane's height also plays an important role, because polygons below the projection plane will be removed as well. Please also bear in mind that the plane's size is responsible for the displacement's scale.

Changing “Open boundaries” to “Yes” will unlock the “@ extension” parameter.

@ extension

When this option is active you have access to the parameters below. As the name indicates, an extension is a method of enlarging the mesh surface and creating the impression of an endless (or at least very large) ocean. When an extension is created, the mesh engine adds a given number of tiles to the original surface and blends them together. The core fluid simulation can be seen as the centre of the ocean. With growing distance from the centre, the mesh's resolution decreases – the polygons become larger. Additionally, you can observe a denser polygon zone around the core fluid mesh which describes the transition from the high-resolution to the low-resolution part.

The Hybrido mesh engine's extension feature can also handle waves near the core fluid's border and smoothes them with the “@ falloff” parameters to create a seamless transition between the core fluid and the tiles. Finally, it is possible to adjust the sea level.

An interesting combination is the usage of the extension feature and cameras: all tiles outside the camera's field of view will be clipped automatically.

@ Uncoupled

With “No”, core fluid simulation and extension are treated as one mesh – the two elements are fused. When you choose “Yes” the parts are stored as two separate files, e.g. “HyMesh01_00082.bin” and “HyMesh01Extension_00082.bin”.

@ Sea Level Auto

By default, the mesh engine calculates the current sea level automatically (in world coordinates). If you want to adjust the level, please change this option to “No”. Then you can enter a new value under “@ Sea level”. Please note that the found value is also displayed in RealFlow's "Messages" window. This value can be copied and pasted to "@ Sea Level" to save time during the meshing process.

@ Sea Level

This parameter is only active when “Sea Level Auto” is set to “No”. With positive values, the surrounding tiles will be displaced. When “@ Sea level” is negative, the tiles are lowered and the core fluid will be embossed. With positive values, on the other hand, the result is an immersion around the core fluid.

@ Fall Off

With this feature you can fade the core fluid waves out to create seamless transitions between the main mesh and the tiles. To activate the falloff and unlock the associated parameters, please choose “Yes”. The falloff area is indicated by two squares. If you cannot see them clearly switch to “Top” view with the 1 key and use the “Bounding Box” mode (7). Please also check if Display > Extension draft is set to “Yes”.

Please note that the falloff option can also be used when the associated “Repeat ±U/±V” values are set to 0.


A mesh ("Bounding Box") with activated falloff:
outer line = mesh's boundaries | middle line = @ Fall Off Offset | inner line = @ Fall Off Bandwidth
@ Fall Off Bandwidth

This parameter describes the area where the core fluid surface is smoothed and is indicated by a dashed square. The bandwidth is measured from the fluid's border to its centre (outside → inside) and given in metres [m]. A value of 0, represents the fluid's border and disables the smoothing effect. The greater the value, the larger the smoothing area.

 @ Fall Off Offset

By default, the smoothing process starts at the core fluid mesh's borders, but sometimes it is necessary to move this border and this is exactly what “@ Fall Off Offset” does. With values greater than 0, the core fluid part will shrink and the flat area (which can be seen as the connection between the extension and the main mesh) becomes larger.

Repeat +U/Repeat -U

Here you can enter the number of tiles in a positive and negative X direction. When Display > Extension draft is set to “Yes” you can see a grid in the viewport showing the adjusted number of repetitions.

Repeat +V/-V

This is the number of tiles in Y/Z direction (the used axes depends on your current axis setup in RealFlow's “Preferences”). When Display > Extension draft is set to “Yes” you can see a grid in the viewport showing the adjusted number of repetitions.