Surface error after filletEdge

[mdesign (Marcin)]

After making filletEdge on the edge between the single-span surface and the ExtrudeCrvTapered product surface I have 100 errors like this.

This is a filetEdge product.

What is that?
How to prevent that error?
How to fix them all at once without manually rebuilding each separately which consumes a lot of time?

bad_srf.3dm (101.5 KB)

[pascal (Pascal Golay)]

Hello- please post the input for this fillet. The problem is there are (nearly) stacked control points at the end of the fillet and it folds on itself.

-Pascal

[mdesign (Marcin)]

Do you know something about giving surface like that to production for CNC. Will it work?

[pascal (Pascal Golay)]

Hello- I do not know specifically but I would not be surprised if these caused trouble. Please post the input, or send to tech@mcneel.com

-Pascal

[mdesign (Marcin)]

Thanks, I will do that later.

Do you know maybe how to detect it in other way than by eye?

[mdesign (Marcin)]

I think I`ve found what causes that. It is because of G0 (lack of tangency) across patches produced from
ExtrudeCrvTapered - that thread: ExtrudeCrvTapered problems (please fix it) - #22 by mdesign

It causes those problems in fillets.

[Gijs (Gijs de Zwart)]

The problem is logged as RH-83398 Stacked controlpoints after filleting edges

I added this thread

[Rhino_Bulgaria (Bobi)]

Finally! Thanks for adding that bug to the pile! I reported it many times over the past years, showed the issue on several videos, yet nobody considered it a bug up until now. Lets hope that it will be resolved for the all people who use Rhino 8 (I know that Rhino 7 will keep the bug).

The manual fix of that bug is to remove (“Remove knot” command) all the doubled end control points and leave just one of them.

[menno (Menno Deij - van Rijswijk)]

@Rhino_Bulgaria Thanks for your reporting up until now. I have - I think - made a fix for this. It would help greatly if you could point to some of these topics, or models you were working with that have this issue, so I can test more and be more confident that the fix created will work across the board.

[Rhino_Bulgaria (Bobi)]

That was years ago, so I have no idea how to find the topics. Most likely I don’t keep the 3d models either, because I simply fix the bug by using the ! _RemoveKnot command. However, I think that some of these videos are still on my YouTube channel, but since I don’t remember the exact videos, it will take a while until I find some examples. Some videos are over a hour long and it’s not easy to find the exact moment where the bug appears. But I’m pretty sure that I fix that bug on at least 5 of my old videos.

[menno (Menno Deij - van Rijswijk)]

Ok, anything that you can find will help - no pressure, I understand that things you worked on many years ago may be hard to find.

[Rhino_Bulgaria (Bobi)]

Good news. I just found one of the videos after a search on my YouTube channel. I will check if I still keep that 3d model somewhere.

Check the 5:35 minute of the video to see the bug with weird shading that indicated a bad geometry there:

Bug with "Fillet" (Rhino 7) - Part 2

After some search on the forum, I also found one of the topics where I reported that bug 3 years ago. That same topic also contains the 3dm model from the video (post #3):

Unwanted diplicate control points after "Fillet dges"

Sure, attached here is the part that had this issue at the lower edge while making a fillet with a radius of 1 mm or smaller (for some reason the fillets with radius above 1 mm were fine). I also uploaded a video showing how I created the part from quite simple surfaces (it should appear online in about 20 minutes after my post). Note that this issue sometimes happens on straight extrusions created from curves with degree 1, 2 or 3 (or a combination of these), so it’s not only related to split …

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I have to correct myself. Looks like Pascal added this to the pile and the bug was supposed to be fixed for Rhino 7 SR11. However, it was left unresolved and I have seen it in Rhino 8 as well.

https://mcneel.myjetbrains.com/youtrack/issue/RH-65216

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I just found two more topics where I reported the bug:

BUG: Duplicate control points after Fillet edge

Quite often I find out that certain fillet surfaces consist between 4 and 7 duplicate control points located at the very end. It only happens on certain radius size, whereas the majority of larger or smaller radii work just fine. In this example, the issue happens when the radius is 1 mm or slightly less than 1 mm. The video were captured last year, but I forgot to upload them at the time. Today that bug happened again while working with the latest Rhino 7 Service release candidate. The bug was …

Rhino's "bad objects"

Here are a couple of examples of bad objects in Rhino caused by the “Fillet” command on relatively simple geometry. In some cases the command generates fillet surfaces consisting multiple duplicate control points placed in the exact same location, as seen in the 1st video: [Bug with Fillet (Rhino 7) 1] [Messy bug]

And another video posted by me in the topic from the last link (check the 1:28 minute):

Messy bug

Here is the 3d model from this particular video. The weird looking fillet is also included:
Random bug.3dm (5.7 MB)

[Gijs (Gijs de Zwart)]

The first linked model seems the same issue and works well in current build of the day.
The latter is a different issue.

[Rhino_Bulgaria (Bobi)]

You mean that the bug will never be fixed in Rhino 7, but is not present in the latest Rhino 8 release?

[Gijs (Gijs de Zwart)]

no, what I mean is that the bug with the fillet that goes haywire is a different issue. I haven’t logged that one yet

[Rhino_Bulgaria (Bobi)]

Looks like we talks about slightly different issues. I meant the bug with duplicated end control points, which is shown in my videos above and reported in 2021. Will it be fixed for Rhino 7, or it will be left unresolved there, focusing only on fixing it for Rhino 8?

[Gijs (Gijs de Zwart)]

Ah, sorry I misread…
No. Rhino 7 development is closed.

[Gijs (Gijs de Zwart)]

@Rhino_Bulgaria

Here is the 3d model from this particular video. The weird looking fillet is also included:
Random bug.3dm (5.7 MB)

RH-83418 BlendEdge curls up

[Rhino_Bulgaria (Bobi)]

I read it this way: Fixing of critical (for the modeling work) bugs in Rhino 7 is closed.

Hopefully these will be resolved in Rhino 9, because I may jump from Rhino 7 to 9.

[eobet]

I wish you could search through your images somehow on this forum, because I’m fairly certain I’ve uploaded images of a few surfaces with these darkened areas over the years…