RKP - Channel Curve (3DS, MYA)

Here you can to draw a curve by setting control points. The mode of operation is simple: just click inside the graph window to add your points. The values in horizontal (X) and vertical (Y) direction can be evaluated with the functions described below. 

• In 3ds Max, on the other hand, values greater than 1.0 can be used and edited directly within the curve. 

• In Maya, all values range between 0 and 1. Higher or lower (negative) values are allowed, but they actually make no sense and we recommend that you only use values in this default range. 

Selected Position

Here you can enter a specific position on the curve's horizontal axis.

Selected Value

Here you can determine the dimension or “size” of the selected channel – the “Channel” parameter itself is available under “Particles Size”. A “Selected Value” is located on the curve's Y axis.

Interpolation

The interpolation defines the curve's “smoothness”. You have four options: “None”, “Linear”, “Smooth” and “Spline”. Each control point can have its own interpolation method; the curve editor blends them together automatically to calculate the curve's final shape. 

With “None”, the curve will be stepped and the values between two control points will not be interpolated, but stay constant until the next value is reached. This results in a stepped curve. The “Linear” mode just connects the control points with straight lines. The result is a jagged curve, as you know from line diagrams. “Smooth” creates smooth transitions between the individual control points. This mode is normally perfectly suited for all kinds of acceleration and deceleration effects, but it here defines how the sizes increase or decrease. “Spline” uses control points with tangents. The curve will follow these tangents until it is influenced by the next control point.

Channel Min Value/Channel Max Value

These parameters represent the channel's values at position 0 and 1 of the curve. An example: Let's assume the age channel's "Channel Min Value" is 2.0 and the "Channel Max Value" is 4.5. Then all particles with an age value smaller than or equal to 2.0 will scaled with 0.0. The particles with an age value of 4.5 or greater will be scaled with a factor of 1.0.

For particles with ages between the range (greater than 2.0 and smaller than 4.5) the scale factor will be determined from the curve.

Finally, the result is multiplied with the "Radius" value from the "Particle Files" panel. If you have enabled the "Radius PP" and "Random Variation" options, the actual size will be changed accordingly.

Scaled By Camera Distance (Maya)

If you want to create a scale change along the camera's look-at vector as well, please enable this feature. The appropriate curve and parameters to control the particles' sizes can be found under “Camera Curve”.