On Jan 8, 2011, at 1:28 PM, John Anderson wrote: > While experimenting with the conversion.sh script, I noticed that > several reported failures are for regions that have an empty tree, or > regions that, when the Boolean operations are evaluated, have nothing > left. When these combinations are passed to the facetize command, the > db_walk_tree correctly returns a null tree, but the facetize command > presumes that a null tree is a failure. I would propose changing the > facetize command to produce an empty BOT (or an empty NMG if the "-n" > option was provided) in these cases. Perhaps a warning should be > displayed that an empty object is being created. > > Does this sound reasonable?
That sounds perfect! We were just talking about that issue right before the holidays and I'd came to the same conclusion, that we needed to support the concept of "null" BoT/NMG objects. Another thought, albeit a little more involved, was adding a new database object representing a generic concept of NULL. So if you had a CSG intersection involving two non-overlapping RPPs and you evaluated the boolean, you'd end up with a NULL object. There's a variety of other places they could be used, including BoT/NMG evaluation. From a theory perspective, the best part is that would complete the object entities needed for general set algebra. We'd also need a complement/not operator (e.g., a u !b + c)), but the code already supports that too. Anyhow, I digress... Sounds great to me! :) Cheers! Sean ------------------------------------------------------------------------------ Gaining the trust of online customers is vital for the success of any company that requires sensitive data to be transmitted over the Web. Learn how to best implement a security strategy that keeps consumers' information secure and instills the confidence they need to proceed with transactions. http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ BRL-CAD Developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/brlcad-devel
