What setting to stop lines looking like twisted ribbons v7?

Rhino Rhino for Windows
1

Hi,
V7
Starting in V7 first thing I spot is when I draw a line it looks like a twisted ribbon with fat and thin alternating parts.
In V5 it was a purer line.

It was twisting away merrily whilst I moved the cursor about for the next click, even more obvious a twisted ribbon whilst drawing.

What setting have I missed to sort out this appearance ?

It seems V7 is a tad thicker contributing to this effect.

RIBBON EFFECT
RIBBON EFFECT1128×705 116 KB

Cheers

Steve

2

In Options > View > OpenGL, what is your Antialiasing set to?
4x is the default for both V5 and V7

V7:

image
image947×399 28.1 KB

V5:

image
image806×654 29 KB

3

Hi

4x for V5 and V7.

RIBBON EFFECT bright then dark repeated
RIBBON EFFECT bright then dark repeated1262×238 61.5 KB

magenta line dark bright dark bright twisted ribbon.

bright dashed effect twisted ribbon V7
bright dashed effect twisted ribbon V71296×319 108 KB

bright yellow segments in selected line, sure as heck was not like this in V5, pure nice lines all the time, it is CAD after all ! comforting to use.

click on images to see the full image res and qlty.

Steve