Matching surfaces

A skrov join.3dm (108.4 KB)

I have matched these three surfaces by position. Afterwards I was able to join two of these surfaces but not the third surface. Can anybody explain Why?

I retried to match the bottom surface again by position and it worked fine. maybe try again.—Mark

One thing seems to be clear, there are gabs or overlaps between edges.
Reported at command:
_CrvDeviation (Srf exploded and edges applied )

A mystery remains,

  1. On one pair _CrvDeviation reports deviation over 9 and this edges get’s joined. Other edges pair has deviation 0.078… and would not join ?

  2. _EdgeContinuity does not reports this deviation over 9.

  3. _EdgeContinuity labels option Distance are allways displayed, checked unchecked.

  4. Changing units from mm to cm, with scale option and a_tolerance 0.001 _CrvDeviation reports deviation only over 5.3…_EdgeContinuity does not reports aggain this deviation.

Has all this its rightness ?

Hello- Run MakeUniform on the surfaces then match them - the lower one is slightly non-uniform, it looks like.


Is _MakeUniform a common got-to command for you when _MatchSrf doesn’t work, or how did you determine to use it in this case?

Unfortunately, _MakeUniform doesn’t provide feedback on whether it actually modifies geometry.

Hi Steve - I saw that MatchSrf, with ‘Match by closest points’ un-checked and surfaces with seemingly idenntical points along the edge failed to line up the edge points to each other, quite, as I would expect. The untrimmed lower surface ‘deltas’ (List command) were slightly off
index value mult delta
0 2.8056777630829992 3
3 2182.2053198513377 1 2179
4 4364.4106397092219 1 2182
5 6557.0793995803842 3 2193
Knot Vector 1 ( 6 knots )

MakeUniform set them all to 1… and everything just worked…


MakeUniform will change the shape unless the knots are already uniform. How large a change depends on the shape and how different the knots are from uniform.

Thank you all for enlightening me in the dark caves of Rhino.
I was not aware of the MakeUniform comand.
I think this forum works really great!