Hi CedUE, Thank you very much for your response and the info. I haven’t tried out the Cluster Group Index system so will look into that. I did have some more luck with fields. It seems if I have multiple GCs in a CU and only pass in the root bone for each GC (zero), then the field applying strain doesn’t seem to have an effect. If I pass in a subset of the child bones as well as the root, then the field does have an effect. I am not really sure why this is the case.