Difference between Rebuild, RebuildCvrNonUniform, and FitCrv

Hi, Ive been using Rhino 7 for about 3 months now and I’ve been using rebuild for everything but noticed it doesn’t seem to go around bends very well, I assume that’s because its rebuilding the curve with all its points spaced uniformly apart from each other instead of concentrating some around the bend. Could any one explain the differences and advantage’s or disadvantage’s between the three different commands and when best to use them.

The resulting surfaces were made using Edgesrf and if anyone could explain the difference in the number of isocurves shown on the resulting surfaces
Thank you.

I think you’ll find the Help articles for each command will clearly describe those differences.
You are correct, Rebuild evenly spaces the points along the curve so it is not suitable for curves that are not uniformly curved.

Why? This is a useful tool for imperfect input but should not be needed ‘for everything’ - do you have an example or two, maybe there is a better approach.


I usually prefer to rely on the “Rebuild surface UV” tool instead (it has a few options in the Command line but I mostly use the “Uniform” one), because it lets me simplify a surface and make it smoother in one direction after it’s already created, thus keeping the opposite direction intact.
It’s also a nice tool to use when I want to match a surface edge to another one with G2 continuity. In this case, I set the number of control points to 6, 7 or 8. Since G2 affects the initial 3 rows of control points, having 7 or 8 control points in a direction leaves 1 or 2 extra points in the middle of the surface for manual adjustment with the “Move UVN” tool.
Also, if I aim to match a surface with G1 continuity, I use “Rebuild surface UV” with 4 or 5 control points. Depending on the situation, sometimes the extra control point in the middle (control point row number 3) that comes with the 5 control points in total is very important to maintain the same height across the middle, whereas control point rows 1, 2, 4 and 5 are affected by the G1 tangent continuity.