Rebuilding surface produces weird CV distribution

Rhino Rhino for Windows
1

First, a papercut:

  • Why can’t rebuild automatically select the current CV density by default? I always have to waste time entering the current counts manually.

Second:

  • Since I’m not changing any CVs in the U direction, shouldn’t they be unaffected by the rebuild?

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Not sure if this is related to this previous topic or not…

(PS. the surface looks like this because the initial rail result was also very weird…)

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This result is the same in WIP, so there’s something I don’t understand going on here.

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Except… imagine the opposite paper cut - you are rebuilding surfaces and you always want say, a 5 by 6…

while I do not like the results here, I don’t see how it would be useful not to change the U as a ‘policy’. That would pretty much negate what Rebuild does - what if it were horrible?. There is RebuildUV, which while limited, might be the thing in this case, with a ChangeDegree to 5 in V after.

-Pascal

3

Ok, so that sounds like there should be a button to copy the current CVs to those boxes… hmm… I think we’ve discussed this already once before… :slight_smile:

Thanks for the RebuildUV tip… that produced the results I expected from the Rebuild command… so I learned something new today! (Still haven’t fully wrapped my head around the difference, though.)

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Hello -

The difference is that in the rebuild direction you can only get degree 3. That is a significant limitation in many cases…

-Pascal

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I rarely use “Rebuild surface” (usually only to simplify a surface to become Point count 2 and Degree 1). Instead, I prefer “Rebuild surface UV”, because it preserves the structure of the control points in the opposite direction. You may also want to play with the several types of rebuild in the command line settings. They give significant differences.

6

This particular bug have been discussed in several topics over the past few years, but I think that the programmers at “McNeel” should take it seriously and try to fix it, because “Rebuild surface” is known for producing highly distorted, unusable conversion of single-span surfaces. That’s pity, because this particular bug in Rhino destroys the general flow of the control points, thus directly impede its users from achieve high-quality surfaces. I wonder, is it going to be fixed any time soon? :slight_smile:

Shown here is an example of converting a simple surface to exactly the same degree and number control points, however, Rhino fails to do the math properly and places the control points in a chaotic fashion which is basically unusable.

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