I think that 3D snapping is already part of the 3D editing enviroment via the snapping dialog. However, 3D snap tips are not available. Thus, enhancements to the 3D snapping and snap tips is what is needed. Something similar exists in the Production Mapping Extension (see "data editing and z-enabled features")help topic.)
z enabled snapping (as aparently available in the Production Mapping Extension) should be part of the core product. Editting 3d objects in ArcMap is painful with manually having to edit the z values, but I find it more stable than editting in Scene or Globe. There was a 3d snapping script available in in 9.3 but doesn't appear to be anything fo 10.
Why do we even have ArcScene? I can't think of another program that needs one program to edit in 2D and a separate one to edit in 3D.
As far as snapping goes the snapping in ArcScene is very badly done, you can barley tell if the point has snapped or not. The Production Mapping Extension is not available in 3D Analyst for some bizarre reason, but its implementation in Arc9.3 was the first really useful 3D editing tool that ESRI had supplied is long suffering user base.
Z Snapping in ArcMap should be standard. If the point has a Z vertice, grab the value, if it doesn't, don't. That, in one sentance, pretty sums up what is required. It can't be that difficult.
Working with 3D features, editing in particular, is far too clunky considering this is 2013. I've developed plenty of workarounds over the years, but would happily give them all up for a native snapping function that includes Z values in addition to horizontal coordinates.
David Triggs says it best:
"Z Snapping in ArcMap should be standard. If the point has a Z vertice, grab the value, if it doesn't, don't."
We're closing this aged idea as part of our continuous review efforts of ArcGIS Pro ideas and since ArcMap is now in Mature Support with no further updates. It's worth noting the following, specific to ArcGIS Pro:
