Hi!
I was looking in the documentation for Eigen3 because I am looking to what the operator * between Transform means. In the documentation web (http://eigen.tuxfamily.org/dox/classEigen_1_1Transform.html#a3001cf5afd95d96a4a229e0c5f817364) it says "Concatenates two transforms". However I don't understand what that means. Is it the same as compounding them?

yes, if T1 and T2 are two transformations and T=T1*T2, and p is a point, then T * p is equivalent to T1 * (T2 * p).