region reg_name op obj [op obj ...]REGION(nged)
NAME
region - create or modify a region combination with boolean operations
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SYNOPSIS
DESCRIPTION
The region command (also available as r) creates a new region combination named reg_name, or adds members to an existing one. Members are specified as operator/object pairs: each pair consists of a boolean operator and the name of an object to include.
The command requires at least three arguments (reg_name, one operator, and one object). The total number of arguments after reg_name must be even — each operator must be paired with an object. Any operator/object pair where the object is not found in the database is skipped with a warning; processing continues with remaining pairs.
Arguments
-
reg_name — Name of the region to create or modify. If the region does not already exist, it is created. If it does exist, the new members are appended to it.
-
op — Boolean operator for the following object. Must be one of:
-
u— union -
-— subtraction -
+— intersection
-
-
obj — Name of the object to add as a member. If
objis itself a region, a warning note is printed but it is still added.
Item ID auto-increment
When creating a new region and the database has a non-zero default item number (wdb_item_default), the item number is automatically incremented and reported. If creation fails after the increment, the item number is decremented back.
EXAMPLES
Example 1. Create a region by unioning and subtracting primitives
mged> region hull.r u body.s u bow.s - keel.s
Creates the region hull.r as the union of body.s and bow.s with keel.s subtracted.
Example 2. Create a region using the short alias
mged> r engine.r u block.s u piston.s
Using the r alias, creates engine.r as the union of block.s and piston.s.
Example 3. Add a member to an existing region
mged> region hull.r u propeller.s
Appends propeller.s (union) to the existing region hull.r.
AUTHOR
BRL-CAD Team
BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org