Best solution for smooth surface transition, FilletEdge or BlendSrf

Hello there, I am trying to smooth the edges of this surfaces (highlighted in yellow) while trying to avoid affecting the existing surfaces too much.

surface fillet or blend.3dm (135.2 KB)

I first went for a FilletEdge but in the end the transition doesn’t seem that smooth in the render view and the Zebra view shows that it is a bit strange and not such a smooth transition. Any suggestions on how to make this look better and keep it watertight.

Hello- FilletEdge will make a G1, tangent transition - if you want a ‘smoother’ transition use BlendEdge. But your middle surface looks a little un-fair, to me, just judging from the zebra. Make sure the analysis mesh is set very fine for Zebra.

surface fillet or blend_Maybe.3dm (3.6 MB)
Note, I replaced the smaller of the center surfaces with a somewhat fairer one.


i think a double curve blend and a double curve network its ok, imho

i misunderstood the question. So try to cut the surfaces using some method and then blendsrf

maybe this way

Thanks for the replies @pascal & @antonio.espositocod !! much appreciated

I tried experimenting with your suggestions and ended up doing 4 options. All of them are based on @antonio.espositocod strategy of trimming. After that two used SrfBlend, one with curvature and the other with G3. The other two are based on extracting the lines and then doing a G3 CrvBlend, after which one used NetworkSrf and the other used EdgeSrf. Not sure how to test which one is smoother or giving a better Vacuum seal/better transition?

Also @pascal I am not sure which surface you replaced or what you meant by fairer? Or how did you do the blend, did you trim something before blending or which command did you use?

surface fillet or blend comparison.3dm (1.1 MB)

Hi Ricardo - this surface -

is a bit messy - some curvature discontinuities and even slight tangent discontinuities- I just made a cleaner version before using BlendEdge or FilletSrf or whatever, in my example.


I see Pascal - many thanks!

And may I know which commands you used to make a cleaner version or any suggestions for checking this mistakes you mentioned?

If it helps for context, the surface you are referring to was made with a loft, then changed the degree and then used matchSrf with tangency.

much appreciated

Hi Ricardo - your surface has a lot more complexity than the neighboring one ‘accross’ (not concerned, here, with the ‘along’ direction)

This is becuse it was lofted (I assume) from the larger surface edge to the edge of the box - these edges have very different structures,
which Loft can only reconcile by making an even more complex surface.

One solution is to extract the edge curves and make sure they have the same structure - in this case, it seems to me we want the structure of the larger surface, so Rebuild the duplicated ‘box edge’ curve to match the curved surface duplicated edge:

Then Loft these curves and MatchSrf to the existing surface - I used these settings:

Simpler, cleaner and matching structures - makes life a little easier when combining surfaces with good continuity.

Incidentally, there is some messiness here to fix up: