Heres one of those VSR multiblends

crossover fillet.3dm (289.1 KB)
just wanted to see how people would handle this in Rhino common. Fairly easy with VSR tools. thanks ,Mark

Hey, can you post a picture? That makes it a lot easier to decide if I want to download the file and then spend time on it.

I prefer to plan out clean flowing topology. Multi Blends are helpful in a pinch like concept modeling or hidden features. I would only do something like this if I knew it was being upholstered.


thank you Jeff I was just about to send it .Now I don’t have to.

That is nice work Stratosfear.

I’d also like to know~

Yes - very nice work @Stratosfear - any chance of seeing a wireframe of that, with the isocurves on?

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I am sorry, but the picture of Stratofear is not a solution for markintheozarks data.
I would like to see how it is done in Rhino5 and if it is not easy, then there should be something like VSR tools in Rhino6.

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That is far from perfect, but that is my solution with common Rhino5.
Could somebody show a better solution, please!

My point is always look for the cleanest topology first. If you have to deal with multi sided openings use trimmed surfaces. Cad packages with powerful fillet commands just eat this stuff up in one go. Multi blends are lazy and usual produce pretty poor results upon closer examination.


Thanks for your reply and comments Stratosfear. Looks like you understand the tools you use well. Yes, starting out with a clear plan of attack must make things run smoothly.

Ed77, great work too. It shows that things can be done quite well , if a person knows their tools. Thank, Mark

A chisel in the right hands

Sweep2 in the middle I understand, but how are you smoothly connecting
the other two surfaces?
I’m also trying to learn blending surfaces coming from many directions…

Here is how I would make this crossover fillet. (see file below)

  1. The blue surface is created with Fin command .125 height.
  2. Green surface is sweep1 using the far edge of blue surface as rail.
  3. Red surface is filletsrf with .125 radius.

You could also make the sweep1 using the edge as a rail, but the fin adds a small amount.of increased accuracy. You could also make both the green and the red using filletSrf if you make the fin a little bit longer than .125 and then use offsetSrf (.125 offset) to create another surface and then you have 2 surfaces to make the green surface with filletsrf. There is very little difference making the green surface as a sweep1 or filletsrf.

crossover_filletX.3dm (312.6 KB)

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Thank you for going through in detail.
and the surface looks nicer than the one done by vsr! amazing…

Doesn’t Fin command extrude a curve normal or tangent ? How did you create the blue surface with that command ?

Yes Fin makes a surface normal to a surface. The opposite edge of the Fin surface is the centerline of the green fillet. You need that curve for the sweep1 rail. You could also get the curve by offseting the surface .125.

The idea is to create the green surface which is an extension of the existing fillet. You need this extension to curve inward because the normal extension of the fillet goes off in a direction that is not usable because it goes past the boss. If the boss had been made big enough then you could use the natural extension of the fillet.

Here is another example of how the fillet could be extended. Not quite as elegant but works OK:

crossover_filletX2.3dm (165.5 KB)

Nice - one less step maybe is to use OffsetNormal instead of Fin.