<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000'>programmatically? <br>a neumann set in moab is usually a set of boundary faces (quads in a hexahedral mesh, or triangles in a tetrahedral mesh)<br>what kind of solver do you have? <br>if you know the tag value, you can obtain the set that has that tag value, with something like<br><font face="courier new,courier,monaco,monospace,sans-serif"> Range neumann_sets;<br> Tag neu_tag;<br> int value_neumann_tag= 100; // your value, set it accordingly<br><br> mb->tag_get_handle(NEUMANN_SET_TAG_NAME, neu_tag, 1, MB_TYPE_INTEGER);<br> mb->get_entities_by_type_and_tag(0, MBENTITYSET, &neu_tag, &value_neumann_tag, 1, neumann_sets);</font><br><br>neumann_sets[0] should be your set. <br><br> then you can get entities from it with<br> <font face="courier new,courier,monaco,monospace,sans-serif"> Range entities;<br> mb->get_entities_by_handle(neumann_sets[0], entities);<br></font><br>Entities should be your quads or triangles. it is up to the specific solver syntax to set pressure on them (or other BCs)<br><br>Maybe I didn't understand your question<br><br>Iulian<br><hr id="zwchr"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;">Hello MOAB-dev, <br><br>Can you please explain how can i set a certain Neumann boundary condition<br>for selected set of faces via NEUMANN_SET tag? <br><br>For example the normal derivative of pressure <br><br>Thanks<br>Anton<br><br></blockquote><br></div></body></html>