Bug: "Soft edit surface" in Rhino 7 is broken

As the topic’s name suggests, the “Soft edit surface” tool (! _SoftEditSrf command) in Rhino 7 does weird things and fails to deliver the expected result shown in the preview wireframe. Rather than soft-moving the selected control point towards the ground level, it will move it to up instead. I captured a video to show the issue:

Hi @Rhino_Bulgaria
I think the discrepancy comes from the fact that you are looking at the control point, when in reality you are moving “the base point”, a point on the actual surface. In order to move it back down, you need to bring the mouse further down as the base point is ON the surface, not at the control point’s position. Note how the base point is a projection of the CP’s position onto the underlying surface. I hope the explanation makes sense :grimacing:
HTH, Jakob

Hi Jakob, the issue is that the preview wireframe shows an expected result which is way too different from the actual updated geometry upon completion of the command. I think that the preview should not be misleading, and instead show exactly what the surface will look like. :slight_smile:

The misleading preview also happens with some other tools such like “Match surface” and “Blend surface”.

Ah, sorry for not getting that! Weird! I’m not seeing it here. My preview is as precise as they come. Strange indeed!

Have you tried with a simple NURBS surface instead of SubD? The surface from my video was a simple planar surface rebuilt to a single-span Degree 5 and 6 Control points.

Hi @Rhino_Bulgaria
That was actually just a NURBS surface (albeit trimmed). Here’s a degree 5 surface - preview still looks fairly precise. I’m woindering if it’s a graphics driver issue messing up the preview?
HTH, Jakob

I use latest Nvidia drivers, so I think that the issues comes from Rhino itself. In the majority of times the preview shows changes that eventually never happen. The control point goes to the opposite direction instead.