ERC Slider - How to do a relative (delta) movement?

Ribanok

Unfortunately, I can only create ERC Sliders which refer to zero position.
Example:
There is a sphere on (x, y, z) coordinates (8, 0, 0).
Now I create a new ERC Slider for that object (create new property, then ERC freeze). The ERC Slider will be at 100% after that.
Next I set this ERC slider to 50% manually. So the sphere will be moved to (x, y, z) coordinates (4, 0, 0).

But here is what I want to do:
There are two tennis rackets and also a sphere.
I want to have an ERC slider which does the following:
0% => sphere is close to first racket. 100% => sphere is close to second racket.

How can this be done? Of course, none of the two rackets are on (x, y, z) coordinates (0, 0, 0) in my example.

Another example could be the door of a car, which can be opened/closed by an ERC slider...

Richard Haseltine

You can't do that with ERC Freeze - it works from the difference between curent and zero values - but you can probably do it with the Property Hierarchy pane by adding a constant to the equation (ERC Delta Add allows this), either creating the links entirely in the pane by dragging and dropping properties from the parameters pane (in Edit mode) to the Sub components of the controller or by using ERC Freeze and then editing the options.

Ribanok

Thank you very much, Richard. It works!

I still don't know, how to use "ERC bake (delta add)" but I found a workaround with your hints:

I make a first ERC freeze on the first position (name a). Also save pose temporary.
Then move the object to the second position.
Then make a second ERC freeze, but create a new property (name b) in the window ERC freeze option.
Then in the Property Hierarchy pane delete everything in sub components of property a.
From property b move everything (but not a) to parameter a.
Load saved pose.