Abstract: Computer apparatus for querying elements of a finite element model. The apparatus includes a tree data structure having leaf nodes corresponding to elements of the model and intermediate nodes corresponding to subsets of elements of the model. The tree data structure is recursively constructed in a working memory in response to initial user command to query a desired model. The tree data structure is traversed in response to user interaction with a desired element of the model displayed in a screen view on a display unit. Within an intermediate level of the tree, nodes in the level are arranged according to spatial relationship of corresponding subsets of elements of the model with respect to at least one axis of a geometric area covered by the elements in a screen view of the model. The tree is traversed according to geometric area in which the desired element is positioned in the screen view of the model.