Please let me turn off 'adult supervision mode' in Rhino

Rhino just told me:
“One input was not extruded because it would have made an invalid surface.”

I’m trying to extrude a close-loop edge, in the specified direction of those two points:

Rhino should never tell me No. What is an invalid surface anyway? The operation seems to work and when I finish it all vanishes, but here’s the preview.

BTW, I was able top duplicate the edge, and find that’s technically an open curve (even if the pipe I had there has no open edges on the seam). I had to pick on of the end points move it away, and snap it back to the start point. Then once it was a closed curved the extrusion work. Are you guys happy now? I’m not, I didn’t need to have valid geometry. This was just to make a sketch, so please stop trying to help me by not serving me invalid surfaces, not cool.


another one…


I agree that Rhino should let you go ahead and make bad objects.

The correct way to handle this would be to allow the user to make the object and then have the Check-for-Bad-Object command identify the object as invalid. They could also identify the curves that make bad surfaces if they are also degenerate. People who don’t care about bad geometry could simply not check for bad objects.

But for some reason McNeel is dead set against Identifying these types of degenerate objects as “bad”. So this is the alternate solution they came up with.

I think, from following the history of things like this here in the forum, that many design decisions are driven not by what you as a competent single user would like, but by what, in the aggregate of all users, provides the least work for John Brock and the others that take support calls.

You may know what a bad object is and when they’re OK and when they’re not, but many users, especially neophytes, don’t and the downstream consequences can create nasty situations that require considerable tear-up and redo. And that’s after the user has finally figured out, often with lengthy help from support, that bad objects are the culprit.

I’ve always thought that there’s no justifiable reason for creating a bad object in the first place; that any object I would draw should be representable in “good” form. But what do I know?

Exactly. All the more reason to have some way for the user to be able adjust the “filter”. Leave it at max by default and let more advanced users adjust it as necessary.

As it is now, the user has no influence whatsoever over what gets flagged or not. That is bad on both ends of the spectrum, there are things currently not flagged as bad that I personally think people should be alerted about, such as when a non-manifold object is created. They’re not considered “bad”, but they can produce havoc down the line.

I have asked for user settable flagging since about V3, I think jim is the only other person who consistently chimes in on this issue.


Most of the time bad objects are made by mistake. Often it is the software that is making a mistake. Good error detection is the best way to eliminate mistakes. Poor error detection may mean those mistakes stay in the software for years or even decades.

I completely agree that the default should be not allow bad objects. I’m sure folks like John, Mitch and a lot of people dealing with data from inexperienced modelers will have a lot fewer headaches. All I’m asking you is to have a switch, somewhere in the settings, where all this censorship :slightly_smiling: can get turned off. I know what I’m doing, most of the time. I’m sure Pascal will say otherwise after seeing some of my files and that maaaaybe I do get myself in troubel sometimes. But this level of limitations starts to feel like I’m using one of the other CAD packages. And I’m not loving it. Please give me my freedom back .