Hello!
I’m using WIP! There seems to be a bug creating a tapered extruded surface from a circle… (Surface/Extrude Curve Tapered)
The resulting surface is twisted. I recreated it from the same curve copy and pasted in version 7, and it extrudes fine.
Thanks,
twisted extrude.3dm (177.8 KB)
Hi, It’d be good to know if this has been acknowledged/logged.
Thank you.
I can’t reproduce this in the latest version and I think I fixed it in the latest WIP. Here was the issue. Can you download the latest and give it a try?
Thanks, it works fine in the latest version.
Bug when extruding tapered is present in Rhino 8 SR5. If I try to extrude with opposite angle -2 ws 2 (or 3 vs -3) degrees it extrudes fine. It doesn’t matter what prefix is. Sometimes it doesn’t work at positive angle and sometimes at negative.
Hi Davor -
Please post a 3dm file that we can check.
-wim
Hi Wim,
Attached is .3dm
regards Davor
tapered.3dm (128.6 KB)
Hi Davor -
What are you using as the input? The red curve?
Can you provide command inputs that make this fail?
-wim
Hi Wim,
yes red curve is the input.
_ExtrudeCrvTapered is command
( Direction DraftAngle=-2 Solid=No Corners=Sharp DeleteInput=No FlipAngle ToBoundary SetBasePoint SplitAtTangents=No )
Davor
If you click: flip angle, result is seen in preview, once twisted once as if should be.
Usually direction I want is not working correctly. If I mirror curve it’s working correctly.
Davor
@davor.pregl I tried to reproduce the behavior you are showing, but did not manage to. If you are still seeing this behavior, maybe a screen recording will help us figure out what you are doing differently.
Screen Recording (28-03-2024 13-01-19).zip (14.3 MB)
Hi Gijs, I attached screen recording.
Regards Davor
thanks @davor.pregl apparently this is a bug that has been fixed now. Doing the same in 8.6 I don’t see what you are seeing.
If you enable statistics and change from Service release to Service release candidate you should be able to get a build that has a fix for this
Hi Gijs,
thank you. During installation I got 3 warnings about links, nevertheless installation finished successfully.
KR Davor
Hi Gijs,
in latest release (from today) and previous one the bug is present again.
D.3dm (29.6 KB)
I tried ExtrudeCrvTapered with negative angle -2 and extrusion distance -4. It twists surfaces.
Difference now is that in preview it shows correct result.
Regards Davor
Also tapered produce small surfaces in corners. I have to:
explode (new solid created)
extend surface (which ends at small triangular surface)
trim surface (with surface in corner)
delete (small surface in corner)
repeat (at all corners with small triangular surfaces)
join solid
make fillets
It is very annoying as I’m mostly constructing molds and I need draft angles and fillets.
Screen Recording (19-04-2024 16-21-54).zip (6.6 MB)
Regards Davor
Welcome to Rhino where the users are expected to be smarter and more competent than the developers.
Extrude Tapered has been broken for 25 years and the users who stick with Rhino for this kind of work have been working around these bugs for just as long.
Personally I prefer to explode the curves before running ExtrudeCrvTapered. That gets me to the same end result with about the same amount of work.
You’re correct that ExtrudeCrvTapered leaves a lot to be desired. I’ve found that Rhinos tapered extrudes really struggle in areas of high curvature or where the input curve self intersects. I assume after you explode and extrude individually you trim the resulting surfaces with one another. Rhinos implementation doesn’t do this which I think is a major part of the problem. Can you show me an example of how they end up looking after your manual process? Even if it’s just a simple rounded rectangle. I think there’s a couple different ways to implement this and I want to know what kind of result you’re after.
If by “struggle” you mean produces crap, then its fair to say that ExtrudeCrvTapered “struggles” on any curve input that is not a planar curve composed of tangent lines and arcs.
Its really annoying the way McNeel always blames the user for Rhino’s bugs.
There are no “areas of high curvature or where the input curve self intersects” in the OP’s input curves. Its not the user’s fault that Rhino makes crap.
The OP already explained in both writing and with a video and with an example file. I can’t see how there is anything else that could be done to make the point any clearer.
As I said, I would do it differently as shown in this file.
Darcs.3dm (103.4 KB)
The curved part of the D is made as tangent lines and arcs. The curves are extended so that after ExtrudeTapered the surfaces intersect. From there I did the same as the OP and trimmed the surfaces against each other. This is the only way to get a clean result from ExtrudeCrvTapered.
I’m sorry I should have been more specific. Your right that there’s nothing wrong with that curve and Rhinos result is still junk. ExtrudeCrvTapered uses offset to generate the curves to create surfaces between. In general when that offset curve self intersects or has a high curvature area that is trimmed away it creates bad results.
So your primary issue with ExtrudeCrvTapered that the filled in corners/trimmed segments parts need to be a single surface instead of separate surfaces?
