People who use splines in their work will certainly know, what I will write about today.

Splajn – especially the three-dimensional one – can cause problems when moving. This may be due to a large number of spline points being close together or to existing relationships (tangentially, curvature etc.).

If you grab the whole spline then you will move it completely! Of course, if he already had any relationships, this will deform depending on the influence of the spline handles. What if he wasn't related – it will just move completely (no deformation).

However, if you select with CTRL a few points and you will move behind one of them – all selected ones will move in the specified direction.

One more TIP.

After switching on Spline control polygon, if you move behind the polygon – you move multiple points at once. But same as above, you can use CTRL to select several vertices of the polygon and move them en masse! It will certainly be easier for you to control the shape.