Hello, There has been some discussion in a pull request <https://bitbucket.org/fathomteam/cgm/pull-request/8/igeom-updates> that I thought would be better brought to the mailing list. This was initially motivated by the realization that iGeom was inconsistent in returning a RefVolume vs a Body in different calls. Thus, two entity handles that referred to the same volume in space would not be detected as the same volume. Faced with two choices - refer only to RefVolumes or refer only to Body's - we settled on referring only to refVolume's in the iGeom interface. However, this breaks the ability to refer to a Body such as my be returned by uniting two volumes that are disjoint - which is part of the interface. So.... perhaps we need to only deal with Body in the iGeom interface. Perhaps Patrick can offer some of the downsides to this approach? Paul -- -- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- Paul Wilson ~ UW-Madison ~ 608-263-0807 ~ cal: http://bit.ly/pphw-cal Professor, Engineering Physics. ~ http://cnerg.engr.wisc.edu Faculty Director, Advanced Computing Infrastructure ~ http://aci.wisc.edu