Caronte - Objects

Owned by thomas (Unlicensed)
Last updated: 28 Apr, 2014
3 min read

Internal Objects

In RealFlow, objects can come from different sources. Under Edit > Add > Object you will find a couple of built-in standard objects, such as “Cube”, “Sphere”, “Rocket”, “Capsule”. By default, these nodes are low-polygon objects and perfectly suited to a quick scene setup where obstacles or containers are required. Some of these objects provide a certain feature that is hardly known: there are high-resolution versions of these nodes available. In detail, the objects are “Sphere”, “Hemisphere”, “Vase”, “Cone”, “Cylinder”, and “Torus”.


Built-in high-resolution objects created with scripting.


The only drawback is that these high-res nodes are only accessible through Python scripting, but fortunately, the relevant commands are easy to understand and to use:

scene.addSphere(4)

Just copy and paste the command printed above to a “Batch Script” window (Layout > Batch Script), and choose “Run” from the editor's “Script” menu. Now you will see a smooth sphere with 5,120 polygons in the viewport. By changing the number in brackets you are able to change the sphere's resolution. The maximum value is 8 and creates a sphere with roughly 1.3 million polygons. For the “Hemisphere” object the workflow is exactly the same:

scene.addHemisphere(resolution)

The other nodes provide similar commands, but some of them require more than one value to define their shape, for example the “Torus”. Here, the instruction is:

scene.addTorus(value1, value2)

“value1” describes the number of subdivisions in horizontal direction, “value2” is responsible for the vertical tesselation.

“Cone” and “Cylinder” take two arguments, the “Vase” requires a third value to define the its opening. With a value of 1.0, it is possible to create an open cylinder with the “Vase” type – an analogy to the “Cube_top_open” node.

Of course, these customized objects support all rigid and soft body dynamics features of their low-resolution “relatives”.

External Objects

External objects can origin from various sources, because RealFlow supports many common 3D file formats, including its own native SD format. Other formats are OBJ, DXF, LWO, MXS, and ABC. MXS is Maxwell's scene description format, ABC stands for the widely-supported Alembic file format. SD files are written from RealFlow or the exchange plugins. SD is versatile format, but there are some restrictions:

  • Only one SD file per scene is allowed

  • SD supports either key-framed animation or dynamically created motion data, but it is not possible to mix both types

  • When one element from a SD file is removed in RealFlow, the entirety of nodes will be deleted from the scene

  • SD files do not support objects which have been created at simulation time

 

Some of these limitations can be bypassed with MultiBodies or the Alembic format. The latter is certainly the best alternative, because it maintains the hierarchical structure of the original scene. The only feature that is neither supported by MultiBodies nor by ABC file is the creation of objects at simulation time. Dynamic fracturing, for example, is currently not possible with RealFlow's export resources and a scene has to be prepared completely before the simulation starts.

External objects are not limited to basic shapes, and you can import any geometry into RealFlow, turn it into a rigid or soft body, and include it in your simulations. However, an object's complexity plays an important role for the simulation process. High-resolution nodes with hundreds of thousands of polygons and vertices will slow down a simulation, therefore we recommend using proxy objects with lower resolutions if possible. However, Simulations with deformations are an exception.