Here's a slightly different formulation of the multi-dimension stuff. 1) no longer dictates the XSD for representing the array. This cuts both ways since you no longer really have an XSD model for multi-dimensional arrays. That is. It is up to the author of the DFDL Schema to insure the needed information about the array (coordinates of each element) make it in to the logical model in a useful way. 2) I added in the complexity of calculating the array size, actually the lower and upper bounds of each dimension, dynamically based on data. This makes the example more real. This still works out pretty well. I'm still pondering whether I like this better or not. I'm thinking about perhaps some sort of pseudo attributes which are guaranteed to be put into XML if you actually render to XML, but where a DFDL API-based implementation can choose not to realize them. Your comments appreciated. ...mikeb