Does anyone know if it's possible to programmatically determine which fields on a matrix item are the matrix dimensions used for that item? I'm working with a client that has many matrix items, each with different dimensions (some dimension fields are shared across multiple items, but some are unique to a specific item). There are other custom fields on the item record that are not matrix dimensions, and I need to filter those out and end up with just the matrix dimension fields appropriate to each matrix item.

load the record and look for fields set with the matrixoption prefix in their id

Which ID are you referring to? The matrix option field is a custom field, and has the standard "custitem" prefix e.g. custitem_window_color.

matrix child items use special fields with the matrixoption prefix for matrix options

Thanks! I have been looking at the parent item, and never knew this about the child items!