SPH - ESpline

Owned by thomas (Unlicensed)
Last updated: 28 Jul, 2015
4 min read

This emitter creates particles and moves them through a force field along a customizable path. The path can be created in RealFlow's viewport directly, imported as a → SVG, or copied from an already existing → spline node. The spline's viewport representation is controlled with the → “Display Spline” panel.

 

 

Affect

With “Force” it takes a little time to display the daemon's full influence and the result is a curved stream of particles. “Velocity” directly affects the particles from the very beginning without any delay or acceleration, and you will get a linear particle stream. “Velocity” is not available for rigid/soft bodies.

Creation

Here are your options:

  • "Axis". The particles are created along the spline's path similar to a curtain. Emission direction is indicated in the viewport's through small arrows at the spline's control points. This direction can be changed with "@ rotation".
  • "Tube" The particles are created along the spline's path. The fluid tube's thickness is defined through the circles at each control point. As with "Axis", emission direction is indicated through small arrows.
  • "Edge". The particles are created at the first control point and moved along the spline through customizable forces. The first point's circle represents the area of emission.
Speed

Here the particles' initial speed is defined in metres per second. Higher values will generate more particles per frame. Faster particles act with stronger forces on other particles or objects. The number of emitted particles also depends on your → “Resolution” settings. A value of 0.0 → stops the emission of particles.

Randomness

To avoid regular emission, it is possible to randomly displace the particles at creation time. Higher settings create more randomness. This parameter accepts all positive values and 0.

Kill leaving

When enabled particles are deleted once they leave the spline‘s boundaries. This limit is indicated in the viewport through circles around the control points. In order to change the circles' radii, go to "@ CP radius".

Close spline

This option creates a connection between the spline's end points.

Reverse spline

If you want to flip the control points' order please activate the checkbox. The control points' indices can be displayed under Node Params > Display Spline > Show CP indexes, but only in “EDIT” mode which is indicated by a yellow frame around the viewport.

Copy spline

It is possible to transfer already existing splines to a “DSpline” node:

  • Click on the “Copy spline...” button.
  • Select a node from the list.
  • The control points and tangents will be used to draw the daemon's path.
EDIT

A click on this button enables the “Edit” mode, indicated by a yellow frame around the viewport. While in “Edit” mode you are able to move (W key) the control points and their handles. You also have access to a selected point's individual “@ CP” settings. Please read the → “Quick Start Workflows - Drawing and Editing Splines” chapter to learn how to shape splines.

@ CP axial

Click on “EDIT” and select a control point to change the parameter's settings. “@ CP axial” introduces a force along the spline's path. Positive values create a force in direction of the spline's last control point, negative values create a force in direction of the first control point.

@ CP radial

Click on “EDIT” and select a control point to change the parameter's settings. “@ CP radial” introduces a force around the control points.

@ CP vortex

Click on “EDIT” and select a control point to change the parameter's settings. “@ CP vortex” creates a rotational force around the spline's path. Positive values create a clockwise rotation, negative values create a counter-clockwise rotation.

@ CP radius

Click on “EDIT” and select a control point to change the parameter's settings. The circle around indicates the forces' scope or radius. Only particles or rigid/soft bodies inside the viewport's circles will be affected. The circles' sizes can be controlled with the yellow dot: hit the R key, select one or more dots, and move it.

@ CP speed

Click on “EDIT” and select a control point to change the parameter's settings. When the emitter is in "Axis" or "Tube" mode it is possible to define different emission speed values for every control point separately. This parameter is given in metres per second and accepts all positive values including 0.

@ CP rotation

Click on “EDIT” and select a control point to change the parameter's settings. Every control point of the emitter has a small turquoise arrow, indicating the fluid's emission direction in "Axis" and "Tube" mode. By entering a positive degree value this emission direction can be changed.

Every control point can be linked to another node, e.g. to animate a point's position. Normally, “Null” nodes are used for this purpose, but any other node will work as well. Simply click on “-” to open a node list.

@ CP handle smoothness

With “Smooth” both tangents are affected while moving a single handle. When you switch to “Broken” the tangents can be edited separately.

@ CP handle weighting

When set to “Even” both tangents have the same influence on the spline's curvature. With “Uneven” the tangents' influence is treated individually.