Creating a smooth surface

I have been struggling creating a surface where ı highlighted in the picture and you can find the 3dm file. I tried patch it helped me to get surface which looks as close as what ı wanted to have but it is not smooth first and second not tangent to the other surfaces where it is supposed to be. Can you help me about how ı can get that perfect surface ?

Thank you.

corner trouble.3dm (164.2 KB)

I’d use Fusion360 for this. You can select individual edges for tangancy.


Hm - it does not look to me like there is a smooth surface that is also tangent at all the edges… Which edges need to be tangent?


Ah yeah it is not clear sorry. 3 edges on chamfers need to be tangent.

Hello - if you DupEdge on the arcs, and use these curves and the chamfer edges as input to Patch (fairly dense I would say) does that come close?



Why is your model tolerance 0.100311?

Thank you Pascal. It worked.

Honestly I don’t really know how and why it was 0.100311. Thank you for your interest.

Quick idea - model the primary domain G1/G2 and then mirror/rotate. Edit: new file, blend curves were missing in the previous version.

Chamfer with equal setbacks.3dm (99.1 KB)


Amazing, Whats the process to get all curves to intersect on one point? How do you calculate the high point?
Thank you.

If you match all three G2 identical (same CP distances to chamfer angle helper surface and chamfer), or if you do one and then copy/rotate to obtain the other two, they will inevitably intersect (the entire thing is symmetrical after all). The “high point” thus emerges by itself, very similar to a round G2 corner or a round corner with equal setbacks. You can then match the curves a bit differently to move the “high point” in or out a little bit (there is leeway).

See a round corner with equal setbacks, which is very similar in approach Corner with equal setbacks.3dm (266.3 KB)

When the three chamfers have unequal chord length or the setbacks have different depth, then it gets a bit more complicated ; )


If you set the point in a plane defined by the mid points of the round corners, it work out pretty well - I don’t know if that is how @Stratosfear has it set up.

corner trouble_PG.3dm (122.2 KB)


This is better than the patch solution for sure. After defining the plane what are the next steps to get this surface? Thank you.

This way, though, one introduces concavities…

Ah, you have me there. Touché



that is look great. What commnad you use for creating 3 surfaces - red, blue, purple?

I’d use Sweep2 and match G0/G1/G2 where necessary, then do a bit of CP manipulation.

There is actually a video tutorial for beginners; it’s for Alias, but the Rhino method is exactly the same.

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Yes, ofcourse :slight_smile: I forgot “match” surfaces. Thank you!