Re: [brlcad-devel] [brlcad-users] Casting RT Structs

[Tom B. <tom...@gm...>]

On Wed, Aug 27, 2008 at 2:12 AM, Christopher Sean Morrison
<br...@ma...> wrote:
>
>> Yep, we've done that before.  But is it correct to say the first
>> region on a path is the "real" region?
>
> If it's the first "positive" region, yes.  The region can't be part of a
> subtraction and you can't just check his parent combination.  You have to
> check all the way up the hierarchy (until you encounter a subtraction) to
> make sure it's not part of a subtraction.
...
> I'd be careful that you're not getting lost in the forest, though.  What is
> it that you're actually trying to accomplish with the tree walk?  What data
> are you needing to get at?  The region structure itself might not really be
> what you should be using as it is intended to be an in-memory raytrace
> structure (hence the trivial access via a hit() callback).

Well, what I really want during this walk is to enter at a tree top
(say 'all') and list every positive region under it (no dups).  For
each region i want all its attributes.

That's it.

Thanks, Sean.

-Tom