Problem summary
The ParticleSpeedLimit node appears to behave incorrectly. The documentations says that "ParticleSpeedLimit restricts particles to a specified minimum and maximum speed."
But if you set its 'minimum' and 'maximum' values to 0, the particles do not stop moving but actually move at the velocity set on the ParticleEmitter node. It appears that the maximum value does not actually restrict the speed of particles.
If you increase the 'maximum' value to a number higher than the velocity set on the ParticleEmitter node, it will actually speed the particles up rather than just restricting their speed.
2) Copy and paste the following code into the Node graph, view the ParticleSpeedLimit node, and play what is in the viewer:
set cut_paste_input [stack 0]version 11.1 v1push $cut_paste_inputParticleEmitter { rate 0.2 lifetime 100 translate {0 -0.5350000262 0} name ParticleEmitter1 selected true xpos -40 ypos -406}ParticleSpeedLimit { maximum 1 max_age 100 name ParticleSpeedLimit1 selected true xpos -40 ypos -340}
3) Double click the ParticleSpeedLimit node to open its properties and change both the minimum and maximum values to 0. Notice how the particles keep their velocity, rather than being stopped.
4) Now change the maximum value to a higher number, 5 for example, and notice how the particles will now speed up.
Workaround
Unknown.
Reproduced by support
This bug has been reproduced in:
NukeX 11.1v1 - Windows 10 - Linux CentOS 7 - Mac OSX El Capitan
NukeX 11.0v4 - Windows 10
NukeX 11.0v1 - Windows 10
NukeX 10.5v7 - Windows 10
NukeX 10.5v1 - Windows 10
NukeX 10.0v6 - Windows 10
NukeX 10.0v1 - Windows 10
NukeX 9.0v9 - Windows 10
NukeX 9.0v1 - Windows 10
NukeX 8.0v7 - Windows 10
NukeX 8.0v1 - Windows 10
NukeX 7.0v10 - Windows 10 - Linux CentOS 7 - Mac OSX El Capitan
Earliest version tested
NukeX 7.0v10 - Windows 10 - Linux CentOS 7 - Mac OSX El Capitan
This issue appears to be in all versions of the product.
Expected behaviour
If you set the 'minimum' and 'maximum' values to 0, the particles should stop moving as they should have a maximum velocity of 0.
If you increase the 'maximum' value to a number higher than the velocity set on the ParticleEmitter node, the particles should keep moving at the same speed because their velocity is less than the maximum limit set on the ParticleSpeedLimit node.
Actual behaviour
If you set the 'minimum' and 'maximum' values to 0, the particles are not effected and move with the velocity set on the ParticleEmitter node.
If you increase the 'maximum' value to a number higher than the velocity set on the ParticleEmitter node, the particles will speed up.
The maximum value on the ParticleSpeedLimit seems to not actually restrict the speed of particles.