I played a bit with “Match surface” in Rhino 8 BETA and fail to understand the logic behind the chaotic orientation of the matched edge in this particular case, while using the “Preserve isocurve direction” option. Before running the command, the control polygon is clearly vertical, indicating that the expected result from using “Match surface” should preserve the same direction of the matched edge. Why Rhino 8 BETA decides to heavily distort the control polygon?
The bug happens with the latest version, too. Simply delete that corner surface, then build a new one with ! _EdgeSrf and apply ! _MatchSrf with the “Preserve isocurve direction” option. Quite strange…
Hi Bobi - I see that this is not what you are after but the starting surface, from EdgeSrf, does not have the isos, or tangent points, I guess, going the ‘right’ way.
I’m not sure why you are using the “Preserve” option here - “Match target” makes way more sense in this case. Also - not sure why you are trying to match those edges to G2, when this surface here is only G1:
ETA - ah didn’t realize at first you were having trouble with the bottom edge - yeah that’s weird! One problem here is that you’re using the Closest option - you should not use that in this case. Try running it without the closest option checked.
Hi Pascal, that bug also happens in many other occasions. This is just one recent example. I don’t think that the matched surface should get so distorted sideways, considering that the target surface is perfectly straight and vertical, and the original control polygon of the former was following a very similar nearly vertical direction.
I’m not convinced that Rhino is doing the best job here, because the “Preserve isocurve direction” option of ! _MatchSrf heavily distorts the control polygon of the upper surface, as seen in this video:
It gets even more interesting when I try to manually place the two distorted control points perfectly vertical above the corresponding control points of the lower surface (History recording is always on during that moment). Once I do that, Rhino suddenly distorts the upper control points in a chaotic fashion again.
Yet another possible bug? For some reason '_ViewCaptureToFile fails to save the proper black colour of the control polygon used in my custom display mode:
Sorry Pascal, that does not make any sense at all.
The preserve “isocurve direction” should deviate as little as possible from the original direction and looking at the surfaces the desired result would be very easy to achieve manually.
Match surface on the other hand not only does not preserve iso direction, it cleary doesn’t achieve tangency either.
