About the filletedge Issue

Rhino
,
1

Why can’t the one on the left be filleted, while the one on the right can? I know there’s a perfect solution, which is using MergeAllCoplanarFaces, so both can work. But I still want to understand why the one on the left can’t be operated on normally, I just can’t figure it out.
倒角问题1.3dm (113.3 KB)

daojiao
daojiao1920×1072 45.4 KB

2

Is it related to the curvature graph of the fillet edge? thank you everyone

qulv
qulv2780×1552 424 KB

3

Probably. There is a kink.

image
image1396×883 217 KB

4

I’m just guessing and don’t really understand the true reason. Why does kink cause this issue? Could you give me some guidance? Thank you.

5

Unfortunately, if you use Filletedge on all the edges in one operation it does not give you a perfect solution. A perfect solution would be a revolved surface ( Surface of Revolution ).

If you first do the vertical edge with the .1mm fillet and then do a second operation of filletedge for the horizontal edges you will get a correct Surface of Revolution where it should be.

The true reason for most problems with filletedge command is that it is based on an incorrect algorithm. Filletedge tries to make one fillet for each edge. In some cases this algorithm does work because the output fillets do happen to match the input edges. But in most real world modeling cases the correct result does not have one fillet output per edge and thus in those cases Filletedge just comes up with something goofy that they have developed from many years of trying to make a failed algorithm work.

6

Thank you very much. I will carefully digest and reflect on the passage you shared with me.

7

I have what I believe to be a relatively reliable and comprehensive explanation. Could you take a look and let me know your thoughts? Thank you so much!

The Fillet Issue in Rhino:
When attempting to fillet an object, if the edges to be filleted intersect with other edges, it may lead to fillet problems. These interfering edges might be automatically selected by the system as part of the fillet path or participate in the splitting process during filleting, resulting in fillet failure or the creation of broken surfaces.

The filleting process involves two critical steps:

  1. Selecting the fillet path.
  2. Calculating the trimming curves.
    Failures often stem from these two steps.

Solutions for the First Issue (Selecting the Fillet Path):
The approach is to manually adjust the distribution of edges. Methods include:

  1. Rotating the object or moving its seam lines and coplanar lines to avoid interference with the fillet path.
  2. Using the ‘Edge of Face’ option in the fillet tool to clearly define the fillet path.

Problems Caused by the Second Issue (Calculating Trimming Curves):

  1. Inability to determine the trimming curves (overlap between the fillet surface and the base surface).
  2. Incorrect calculation of trimming curves, where additional edges participate in the trimming process, leading to broken surfaces.

Solutions for the Second Issue:
The approach is to eliminate additional interfering edges. Methods include:

  1. Using MergeCoplanarFace to merge coplanar surfaces and remove coplanar lines.
  2. Adjusting the fillet radius using the slider, with the help of the preview, to cover the broken surface areas.
  3. First selecting specific edges to fillet (using the preview to avoid broken surfaces), then filleting the remaining edges, and finally manually trimming and combining the results.

Important Note:

  • For objects with obtuse angles, the probability of broken surfaces is lower.
  • For objects with acute angles, the probability of broken surfaces is higher. However, by adjusting the slider with the help of the preview, the issue of broken surfaces can be resolved.
1 Like
9