Why does Rhino have lots of issues in filleting complex surfaces while Solidworks usually fillets easily?

Is it true that Solidworks has better filleting tools? Filleting complex surfaces has much pain. It usually fails.
What priveleges does Rhino have over Solidworks?


if you really want to know which is better you have to find out for yourself, there is a lot of stuff being said out there. Solidworks seems to have a few nice options during fillet but fillets are in general not the best in any software, they all fail sooner or later depending on the complexity of the surfaces. here 2 examples i found on the net where Solidworks does not succeed.



MCAD products generally have better filleting because traditionally that’s…well that’s one of the main 2 or 3 things they are FOR, so I’d hope they can do it. Also, being ‘feature based’ probably makes it easier for the program to figure out what strategy to apply in any given situation.

Rhino’s advantage is if the filleting fails, you can take what Rhino gives you and fix it up yourself, as opposed to having to redefine the part to get the parametric fillets to work.

Also, when working on a complex curvy model it can be faster and easier to work with loose surfaces and FilletSrf in Rhino than to try to first make a complete closed solid then apply regular filleting–sometimes you don’t really know what your ‘unfilleted’ shape should look like, but if you just lay out surfaces and start adding FilletSrfs between them, the result you want will intuitively appear.


Here’ a link to a relatively long but excellent video about using Rhino and SolidWorks.
The presenter covers the filleting differences and issues that plague both Rhino AND SolidWorks.
It’s worth the 30 minutes to watch it.


I don’t think that’s true. If you look at rolling ball fillets that are made in Solidworks, you will see that all the fillets work exactly the same as they do if they are made with FilletSrf in Rhino.
In other words, all the individual rolling ball fillet surfaces in solidworks are a round connection that is tangent to 2 surfaces just exactly like the fillets you make with filletSrf.
There is really nothing in the making of fillets that requires any knowledge of features or parametrics.

Rhino could have powerful filleting if they would just automate the filletSrf process and that would be very easy to do.

Well not really.
Whereas FilletSrf makes the same correct surfaces that Solidworks makes, FilletEdge makes incorrect fillet surfaces.
Filletedge makes some surfaces that shouldn’t be there and fails to make other surfaces that should be there. And even the surfaces that are supposed to be are often inaccurate and out of tolerance. So how is a user supposed to know what is good and what is not?


Well… if that’s the case, please knock it out of the ball park for us, Champ!


Wouldn’t that be nice?


What reason do you have to doubt that it is not the case??
If you want to pay me to do your filleting (do it correctly) in Rhino, I’m available at $80/hr

As I said, FilletSrf can make any rolling ball fillet that Solidworks can make. The only reason Rhino users don’t
use FilletSrf very much is because the user has to tell Rhino where to put each fillet by clicking twice with the mouse for each surface. The problem, is not that Rhino can’t make the fillets, the problem is the user input is clunky and tedious so most people don’t want to even bother trying;

It would be extremely easy to improve the user input. The problem is all the development time is spent on FilletEdge.
As far as I can tell Filletedge today is no better than it was in Rhino2. If 1/10 the development time was spent on making FilletSrf more user friendly it would be a huge step forward for many users who would like to make fillets in Rhino that are just like the fillets Solidworks makes.


Since i don´t use filletedge for my modeling anymore since some years ago and switched to blend fillets or filletsrf i realized that rhino don´t has a fillet problem. It has a trim problem. Fillet edge allways fails on the same typical points and you see that the problem often looks like a trim problem. With filletsrf you fillet nearly everything but it´s not very comfortabel and you see a difference to the trim layout of fillet edge. Joined Polysrf fillet by hand create also much better offsets. This is just my experience.

Sometimes the command: filletedgeold works better than filletedge. You must type in the hole word.


Rhino does what he can. It does not have a performing kernel in this aspect (filet), it is neither Acis nor Parasolid. In fact, if we reflect, programs like Rhino, such as Moi or SolidThinking, use, for this kind of operation, more robust kernels (those mentioned earlier).
I also believe Rhino v7 or v8, etc. it can not offer any significant improvement, no revolution, little adjustments yes, but nothing magnificent.

Rhino is suitable for other operations, for other uses …

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It´s a freefrom surface modeler nearly without any limitations to the user. I really like that. Many people don´t - especially if they started 3d on parametric CAD systems. For me the fillet problem isn´t that kind of important. I see it as the entrance card to work with no restrictions.
Furthermore i think the CAD world is the only product range on the world where people compare products with that price differences. In comparison to it´s price it´s the absolute most powefull and flexible CAD system available with the most fair license system to the user. All most important file types are supported for … nearly nothing.

Can anyone still see a fillet problem.


That statement is false. Rhino has the ability to create the same rolling ball fillets that the Acis or Parasolid kernel produces using Rhino’s filletSrf command. The problem is not that you can’t do good filleting in Rhino, the problem is that creating fillets one surface at a time is more time consuming and requires more effort than most users are willing to shoulder. No effort has been made by McNeel to ,make this work faster and easier even though the simplest improvements would be easy. .

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The difference you see is the difference between correct fillets and incorrect fillets.

That’s definitely true.


Don´t want to start a new class A discussion but I often saw that surfaces created by automatic tools with lots of control points are also one reason for fillet problems. It´s not only rhino its also the user.

Does anyone know how much the system settings affect the fillets?

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I agree with you. The way forward should be by expanding the options and usability of fillet surf.

I wouldn’t call ~$1000 “nearly nothing”, but I agree with your main point. :slight_smile:
I personally think there’s two reasons for the extremely high cost of “professional” CAD software:

  1. To provide an entry barrier to “ordinary folks” obtaining professional level tools, thus protecting their customers from competition.

  2. As a result of 1, the cost per copy needs to be much higher to support a development staff of sufficient size to keep the high-end features rolling out.

I have no idea how big the developer and support staff for, say, CATIA is in comparison to Rhino’s, but I wouldn’t be surprised if it’s an order of magnitude larger.


So how exactly would you expect a more sophisticated FilletSrf tool that does not require edge input like FilletEdge, to work? What is the overall workflow going to transform into? What about the incredibly simplistic interface and function of FilletSrf (and TestSphericalPatch) makes you think that trying to add the slightest bit of intelligence to reduce clicks and handle some of the cleanup–to a level that YOU are going to approve of!–is just a hop, skip, and jump away? And I DO use FilletSrf virtually all the time now, I’m aware that it seems like a tedious process that should be easy to automate, but I’ve done enough coding to know that’s not necessarily so.

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In Germany 1000€ is also not nearly nothing. But 20 times more nothing than in so much other countries around the planet. For this you get a professional tool that helps you to find good jobs or to start your own freelance experience. For a few money more you buy for example a octane license or another plugin and in a short time you have 3 or 4 additional tools in your portfolio. Ok- Autodesk grabed some cool tools- but there are a lot helpfull low priced plugins. Is there some other business were you can start so easy? Of course that doesn´t mean that you become the new rockstar in the worldwide design / 3d business. But once you payed, you can work and work and work and try your best.
I don´t know all CAD systems (maybe there are some other low cost tool) but i have no idea how you start your business with one of the big market leaders in a official way. I know that lot´s of people starts semilegal in their job business after school because they can´t pay 10000 Euro for a one year license.
I don´t say that a good software solution must be cheap - it can be expensive if it´s worth the money. All the development stuff over years is crazy.

I don´t like the way how some big market leader split the Software systems and offer to you in funny little parts and totally different license and payment systems. From my job experience with smaller companys (10-100 emplo.) i can tell you that many company leaders are totally pissed of after a short time by hidden cost or massive extra cost because of some small additional features only available in crazy combinations. ( Of course it´s helpfull to break down massive software systems in some main parts with different features for different clients).
Furthermore it´s absolute obvious that the most license and upgrade systems are just made to earn more money and to fix you hard to the company.
If you interested in a bigger cad systems and want to know the costs- i don´t know- it´s a secret to get some basic informations about. Why?
Some companys ban you from upgrading to the next Version once you stopped the maintanance for half a year.
I don´t want to be the owner of a engineering office with 20 employes. You must work long and hard for all the licenses.

From this point the cost for rhino are really going nearly to nothing (upgrade 500,- Euro)

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And the conclusion is, like in any CAD forum since the 1980s (we had bulletin boards back then), that CAD software should do everything perfectly and cost nothing, while the user is fully entitled to billing top dollar ; )


No. From my point of view Rhino is to cheap and far away from perfect. I don´t want all for nothing. All my software is legal. If you like these license systems it´s ok. And because of this massive price difference i have no problem to make my fillets by hand.