Hi Peter! I downloaded the demo version of Cyberstrak 2.0 for Rhino 7 and tried its various tools. The “Extrapolate” mode of “CSCVModeling” works flawlessly.
However, I failed to find a way to move a bunch of selected control points by gradual extrapolation. Sort of a partial “Extrapolate” that will ignore the non-selected control points.
In this example, I added a number to each handle that moves the selected control points. Handles 2, 6, 7 and 9 are primary handles, i.e. they move the entire end with the same distance.
For example, if I drag handle number 2, it will move handles 1 and 3 simultaneously with the same distance, too. The control points at the other end (handles 8, 9 and 10) will move by 50% less distance.
However, if I frag handle number 1, it will move 25% more than handle 2, and 50% more than handle 3. The idea is that when you drag an extreme outer handle by a certain amount, the opposite end of the selected control points will move gradually slower. This means that the opposite control point near handles number 10 and 12 will move the least.
Partial interpolation arrows (only the selected control points are affected, the rest ones remain intact):
After dragging the common handle number 9 (areas 8, 9 and 10 move the most, areas 1, 2 and 3 move the least):
This video shows where a new “Partial extrapolate” would be much helpful:
To increase the productivity, I suggest to enable seeing the modified surface in the same display mode as the rest surfaces. For example, I’m a heavy user of the “Light lines 5 Plus” display mode, but when I activate the “CSCVModeling” tool, it renders the surface to be modified in a semi-transparent blue material, with the back geometry seen through it. This makes it impossible to use the coloured stripes of the display mode (or any environment map of other display modes, or any material assigned to the surface) as a reference for the surface quality.
It would be nice to be able to use custom colours for the Curvature graph, which will improve the visibility while using a bright surface material or a display modes that use bright environment map.
Another suggestion regarding the Curvature graph. Make it possible to use different scale factors for the U and V directions. Currently, both directions use a common setting, which forces me to often click on the “Auto scale” button or manually set a custom value in the “Scaling factor” field when I change the direction from U to V, or vice versa. For example, surfaces are that more curved in the U direction that the V direction, need very different values for their directions. U direction may need a scale factor of 100 000, while the V direction needs a scale factor of 20 000 to achieve graphs with relatively the same height.
It would help if the user could enable both, U and V directions to be visualized simultaneously. Perhaps that could be made by replacing the “Invert U/V” tickbox with two separate tickboxes called “U” and “V”, respectively. 
Obviously, when you change the numerical values of the scale factor, they should affect only the active direction. For example, if I enable only the U direction and set a value of 100 000 for the “Scaling factor”, it should not affect any settings for the inactive V direction.
About “Shaded deviation”. It’s a great idea to be able to cycle between the different modes of “Projection direction” with the mouse scroll wheel. However, my suggestion is to not open the “Cplanes” pop-up menu while rotating the mouse scroll wheel, because it interrupts the cycling bwtween the modes. The “Cplanes” pop-up menu should appear only when the user is pressing the “Projection direction” button and clicks on “Cplanes” from the dropdown list. If you can make this little enhancement, it will let the user cycle the different modes with the mouse scroll wheel back and forth without any interruption.
Also, the “Density” setting may include at least 1 or 2 more dense steps, because the current “very fine” setting is not fine enough for slightly curved surfaces that are almost straight. Perhaps adding a “German over-engineering” or simply “German” setting (several times more fine than “very fine”) setting will do the job.
“Transition analysis” has one bug. When I set “Scaling factor” to 1000 (clicking on the “auto scale” also sets it to 1000) and press the upper arrow to increase the factor, it changes to 0,0001, which is confusing, because the expectation is to increase the number by 100 with each click after the number is already 1000.
Here is a sample 3dm file to test this particular case where selecting “Tangence” and pressing the “Auto scale” button sets the scaling factor to 1000. Then you have to press the upper arrow to increase the value by 100 to set it to 1100:
Test in Cybestrak with Transition analysis.3dm (982.4 KB)
About “Sections”. It would be nice if changing the number of sections (“No. Sections”) does not require to press the “Apply” button when the value is changed by the tiny up and down arrows, and instead offers an immediate result.
Another thing to consider is to prevent the accidental deselection of the selected surfaces. This happens when you examine just a few selected surfaces, and then press the “All” tickbox by accident. If you turn off the “All” tickbox again, the tool will not bring back the previous custom selection. I suggest to remember the custom selection, in order to keep it for when it’s needed after switching the “All” tickbox on and off. The custom selection state must be remembered unless it’s replaced by another custom section. The “All” tickbox must turn on the sections for all the geometry, but turning it off again must bring back the last selection of surfaces.
