There was some recent discussion about rebuilding the "Direct tree" on the Chessreviews mailing list. I felt that a short article about this topic would be in order.
Within Chess Assistant, the term "Direct tree" is used to refer to a type of tree in the generic sense. However, it also refers to a specific tree viewing configuration. You can see an example of the latter when you click on the drop-down menu that changes between the various tree configurations (i.e. default, current base, hugebase, direct tree).
In the generic sense, direct trees are used to construct opening books, and to speed up access to database statistics, which can be viewed with specific tree configurations. If all this sounds confusing, then it is best simply not to touch the tree files, and skip the procedure in this article entirely. Indeed, 95% of Chess Assistant users should never really need to concern themselves with the process for constructing a direct tree.
This article concerns itself with the process of updating the trees used when you click on the drop-down tree menu. It turns out that for Chess Assistant 7/8, these files are called d2m.elm and d2m.hsh, and are located in the Chess Assistant root directory. Why would you want to update these files? Well, this set of tree files is built from hugebase. When you add files to hugebase, the statistics present in d2m.xxx do not reflect the contents of hugebase. So for example, when you are using the direct tree viewing configuration, you might see that a particular variation was played in five games in the direct tree, but when you actually go to open the five games in hugebase, there will be six present instead.
If you want to avoid this issue entirely, simply use the hugebase tree - it is automatically rebuilt if you use Chess Assistant's automatic update feature. But for those that are using slower hardware, and want to use the direct tree instead, they can update it with the help of this article.
The procedure is as follows:
Now, you could also avoid the process of copying/overwriting these files, and simply change the tree configuration for the "Direct tree" settings, so that they point to hugebase.elm and hugebase.hsh. To do this, hit Alt-f7, and click on the button labeled "Edit configurations". Then double click next to the primary moves and statistics entries. You should then be able to change these entries to the hugebase tree that you built earlier.
Ok, that's it, have fun!