ERC-bouncing ball puzzlement

protovuprotovu Posts: 194
edited December 1969 in Carrara Discussion

I am a new user of ERC, and am hopeful that I will be able to put it to good use.

My question:
In checking out the ERC-Bouncing Ball, I have tried to "take it apart" in order to try to understand its workings. One thing that has me really puzzled is how the Ball (body) has morph targets which are 1. un-deletable, and 2. controlled by the ERC with no keyframe association in the sequencer. Am I missing something obvious? Even more puzzling...I am able to add morph targets to the ball that respond to the ERC with no keyframing from me. I would like to be able to exploit this function once I understand it.

Thank you for your help,


  • WendyLuvsCatzWendyLuvsCatz Posts: 26,535
    edited December 1969

    Fenric probably can answer better but try looking in the modifier tab
    that is where I used ERC the few times I tried it
    it has the option to add ERC in modifiers and in those added modifiers are various parameters

  • protovuprotovu Posts: 194
    edited December 1969

    Hi Wendy,
    I did look in the modifier tab. Can't see anything that relates to morph target key frames as they would exist in the master objects section of the sequencer. No hidden, and no partially hidden morph targets. Maybe Fenric will inform on this?

  • wetcircuitwetcircuit Posts: 0
    edited December 1969

    Try contacting Faba, she wrote several tutorials on ERC (find them at

    Have you tried the ERC Inspector? It may give you more info about what is going on.... ERC is a bit cryptic. If you figure some stuff out, please share!

  • rk66rk66 Posts: 372
    edited December 1969
  • FenricFenric Posts: 351
    edited December 1969

    I'm not sure why you can't delete the morph targets - that has nothing to do with ERC. As far as keyframes go, that's the point of ERC: it doesn't use them. The values are re-calculated at each frame based on the parameters you specified, they are not tied to keys.

    ERC needs two basic things: something to be controlled and something to do the controlling.

    So, look at the "body", the modifiers, there is an ERC using "advanced" options. The "something to be controlled" is the morph "stretch". The "something to do the controlling" is the "Foot", specifically the Z-coordinate.

    The control type is "Set". This means that the value of the stretch morph will be set to the controller value.

    The modifier is "Subtract" with a value of 1. This means that 1 will be subtracted from the controller's value.

    It is in absolute mode, so the calculated value will replace whatever might have been, ignoring any keyframes or manual changes.

    SO... at each frame, ERC will

    go and fetch the Z coordinate of the Foot.
    subtract 1 from it
    and set the value of the stretch morph to the result
    overwriting any other value that might have ever existed.

  • protovuprotovu Posts: 194
    edited December 1969

    Thank you Holly, rk66, and especially Fenric for taking a moment to help me.

    Fenric, I will dig back into this now. I am sure this information will help a great deal.

    I look forward to being able to put this to good use.


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