Hi @Maxim ,

Yes it is Geometric-Center, then I use MOVE command to move the "desk" object using this command sequence:

Command: MOVE
Select objects: 1 found <- Select desk
Select objects: <- Hit Return
Specify base point or [Displacement] <Displacement>: _gcen of <- Use Geometric Center object snap
Specify second point or <use first point as displacement>: #0,0 <- Type this and hit Return

I have a problem with this step:

<- Use Geometric Center object snap

After typing "_gcen", "of" will appear after typing space, then how can I snap the full object? It does not show a small green triangle of central part of an object.See my attached screenshot.