# Match continuity across multiple intersections

Hi dears
How can i match geometric continuity across multiple intersections?
for example as you see in the below picture :

Matching surface’‘1’’ with surface’‘2’’(G2 continuity-Average surfaces) adjusts the three rows control points(V direction) of surface’‘1’’ . Then when i want to Matching surface’‘1’’ with surface’‘3’’(G2 continuity-Average surfaces) adjusts the other three rows control points(V direction) of surface’‘1’’ that means for (G2 continuity-Average surfaces) we need at least six rows of control points( V direction) for surface ‘‘1’’. Now i want to matching surface’‘1’’ with surfaces’‘4’‘and’‘5’’ like surfaces’‘2’’ and ‘‘3’’ ( G2 continuity-Average surfaces), these 2 matching adjust the six rows control points(U direction) but destroy adjusting rows control points(V direction) so i lose my previous G2 continuity between surface’‘1’’ &’‘2’’ and G2 continuity between surface’‘1’’ &’‘3’’.In the other word i can’t match surface ‘‘1’’(G2 continuity-Average surfaces) in four sides.

What should i do?

Hi Shayan- a lot depends upon the relationship of the surrounding surfaces - the marked points, below, are needed to match to both #2 and #4. There may or may not exist a position for each of these that satisfies the matching conditions for both surfaces at once.

But, you can use the MultipleMatches option to do all four edges at once- see how that works.

-Pascal

Hi dear pascal
I got it , thanks for your attention .
Can you introduce me a tutorial video or article or book that learn technique of continuity across multiple intersections
Thanks

This is exactly what I’m struggling with right now.
In my case, the multiple selection won’t work.
Is there a way to manually manipulate the surrounding surfaces CV’s so that the shared CV’s line up, and conditions are fulfilled for each continuity?
Not in a straight line though, that’s easy - but in a curved fashion?
I tried using arcs for this, but couldn’t get it to work.
Hope you understand what I’m talking about, otherwise I’ll post an example.

Hi @shayan the following two videos provide some interesting techniques that might help you:

And especially this one

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Yes, I watched those.
The blends are stacked with cv’s though.
But perhaps there is no way to do it cleanly when we’re dealing with trimmed surfaces?

How about extracting isocurves from these surfaces and use them as guides for matching/blend the curves between them with g2 continuinity. Then you can do sweep2s or or surface from network of curves? You still might need to match the surfaces with the sweep2 surfaces though.

the last video is showing a rather bad approach to solve these kinds of blendings. If this thread stays active until the end of this week I might be able to show a better surface layout.

Its all about layouting the surfaces. Besides the surface layout what immediately catched my eye was the useless use of g3 blendings. Usually filletblends are only g2 and in corner blends g1 only. Its more about surface smoothness rather then transition. So matching g1 at difficult areas is totally okay and yields better highlights as higher continuity, because you can equally distribute controllpoints. Equally distributed controlpoints means smoothness and means better reflections. Same goes for cp-count. less is more…

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Would love to see an example!
In the end I installed the good ol’ VSR plugin, which makes clean blends.
But still it would be nice to be able to handle it manually in cases when automation fails!

Absolutely,

I am also extremely interested in seeing how things can be approached better!

Thanks

hi dear nick thanks for your attention