Hi anto, yeah that's a good example of where "Planar sections" can help!

By default Blend makes each side of the blend come off perpendicular from the edge curve. But around bends that can then cause bunching like this:




When using the new "Planar sections" option, it uses a different method, the cross section for each blend goes on a plane. First it makes a line connecting the two opposite sides of the blend, like this:


Then it selects a plane that passes through that line. The plane is selected by using the "up direction" that you pick when you trigger the planar sections option. When you draw the "up direction", it basically specifies a family of planes that can pivot around that direction sort of like this (also called a "pencil of planes") :




The way that helps is that with each cross section completely on one of those planes it can help avoid them crossing over into each other which is what makes that kind of awkward bunching effect.

When you turn on surface control points in both of those cases you'll see the difference, with "Planar sections" each row of control points in the blend direction will be all on one plane.

Another example - without planar sections with the blend coming off perpendicular to each edge:


With planar sections - direction picked upwards along z axis:




One row of control points in the blend, note how they are all along one line when viewed from the top:





- Michael