.. _boundary:

&nbsp_place_holder;

> **_BOUNDARY_**

>

>> The boundary routine operates on the current mesh object. For the nodes
lying on the specified surface(s), it sets the specified node based attribute
to the specified value. Optionally boundary will call the user supplied
subroutine set_user_bounds [(see IV. e.8)](../miscell.html)

>

> FORMAT:

>

>> **boundary/dirichlet**/attr_name/[value|identifier]/surface_list

where:

>

> **dirichlet**

> is currently unused but must be specified&nbsp_place_holder;

>

> attr_name

> is the name of the attribute to be set&nbsp_place_holder;

>

> value&nbsp_place_holder;

> is a constant, and is the value to which the attribute is set

>

> identifier&nbsp_place_holder;

> is a character string that will be passed to

>

> subroutine set_user_bounds&nbsp_place_holder;

>

>> > surface_list is one of:

>>>

>>>> > > > **-all-** (all boundary nodes)

surface_name/**inclusive** (all bndry nodes on surface)

surface_name/**exclusive** (all bndry nodes ONLY on surface)

surface_name/ (same as exclusive)

surface_name1/surface_name2/**inclusive**

(all bndry nodes on the union of the surfaces)

surface_name1/surface_name2/**exclusive** (default)

(all bndry nodes ONLY on the intersection of the surfaces)

surface_name1/surface_name2/ surface_name3/.... (same as exclusive)

>

>

EXAMPLES:

>

>> **boundary**/**dirichlet**/vd_v/7.0/**-all-**/

sets the attribute vd_v for all boundary nodes to be 7.0

**boundary**/**dirichlet**/vi_s/8.0/pbot/   
**boundary**/**dirichlet**/vd_v/9.0/pbot/**inclusive**/   
sets the attribute vd_v for the nodes that are on the surface pbot to be 9.0

**boundary**/**dirichlet**/vd_s/13.0/pfrt   
sets the attribute vd_s for the nodes that are on the union of the surfaces
pfrt and prgt to 13.0

**boundary**/**dirichlet**/vi_t/12.0/prgt/   
**boundary**/**dirichlet**/bconds/top_plane/s1,s2,s3/   
will pass the set of nodes on the intersection of surfaces s1,s2 and s3 along
with the string top-plane to subroutine set_user_bounds.