Hi Dave, thanks. I'm new here, don't even see a way to attach frame grabs, but if I can offer a clearer description of the scene. One mesh, about 8-million polys, is of the floor of a section of cave. It overlaps with a second mesh, the left wall of that passage. It would take forever to precisely align these two behemoths translating and rotating from their respective points of origin. So, the approach is to identify 3 features common to both meshes and align those by position, allowing rotation to follow. Clear so far? I've created null objects at the three locations common to both meshes, so 6 total. I'm thinking I need to constrain one null of one mesh to that particular vertice it's closest to, using only translation. I'm thinking I need to do this for each of the remaining 5 nulls. And then, I would think I could simply snap align one null on mesh 1 to its corresponding null on mesh 2 to bring the first common point into registration, step and repeat for common points 2 and 3. This is generally how data sets from LiDAR scans are connected using various spheres physically set in a scene common to two survey stations, though I'm not using LiDAR, but the joining of two overlapping meshes is the same, so it follows that the approach would be similar. Thanks for your help! Benjy