The primary output of the Revolve Channel Modifier is a world space distance traveled along a specified vector, as well as outputting a distance traveled the modifier also has channels to compute a rotation value from a given radius and a percentage traveled along a specified length. The former is useful for driving wheels on a vehicle for example.
Input: Position: Link the World Position transform of the item whose movement is being measured.
Input: Rotation: Link the World Rotation transform of the item whose movement is being measured.
Input: Radius: Taking a radius set in this channel the modifier will calculate the rotation required to roll a cylinder over the distance traveled without slipping and output it to the 'Angle Output' channel.
Input: Length: Given a length set in this channel the modifier will output the percentage of this length traveled to the 'Percentage Output' channel.
Input: Adjust: This channel can be used to alter the outputs of the modifier, by default it is set to 100% meaning that the output is not affected. By setting this to 0% the output is static and at 200% the outputs are doubled. This can be used for things like braking, wheel slip etc.
Input: Axis: This channel sets which of the direction vectors defined by the Position and Rotation transform inputs is used to work out the distance traveled.
Input: Negative Axis: Enabling this setting will cause the modifier to use the negative axis of that chosen in the above channel.
Output: Angle Output: This is the angle of rotation calculated from the 'Radius' channel. Connect this to one of the rotation channels on the Rotation transform of the driven item.
Output: Percentage Output: This is the percentage of the 'Length' input channel traveled. For example, if the distance traveled is twice as long as the input length then the output will be 200%.
Output: Distance Output: This is the total distance traveled of the driver item along the vector specified by the 'Axis' channels.
Notes on using Revolve--
Cache:This modifier uses a cache to store the total distance traveled, it may become necessary to reset this cache periodically when working in the scene, especially after a lot of scrubbing or jumping to different points in time. This is achieved by pressing the 'Reset' button found in the properties form for the modifier.
Network Rendering: Scenes using this modifier will require the output to be baked and the modifier removed or it's outputs unlinked in order to render over a network. This is not necessary when rendering locally provided the frames being rendered are in sequence. Resetting the caches on each modifier before baking or rendering locally is advisable. The caches are not stored in the scene file so will be reset automatically on scene reload.
Dependency Loops: To avoid a dependency loop, do not use the world position and rotation channels of the item being driven as inputs to this modifier. Create a locator at the same position as the driven item and parent the driven item to it. The world position and rotation channels of the locator can then be used as inputs for the modifier.
