Hi Holger, where is it that you're trying to put the fillet?

One thing that will be problematic for filleting in your case here is that you some very narrow surfaces and filleting will fail if the fillet is large enough that it would completely consume away an existing surface. So you'd probably be limited to a very small fillet radius here.

The problem area would be in spots like here:





That's a pretty skinny surface, only about 0.02 units wide - if the fillet you want would need to eat that totally away it won't work.



Another problem area can be if you have 2 surfaces that come close to being smooth to one another but are actually not entirely smooth with say a 5 to 10 degree very shallow crease between them. It looks like you have some things like that in this model as well, that would be spots like this:




As 2 surfaces get close to smooth, any fillet between them starts to become very small in size itself and when it gets too small it can make the various calculations difficult to process very well.


Sometimes it can be better to make an initial model that has all very distinct sharp edges in it and then use filleting to put in all the rounding, rather than trying to create rounded surfaces using sweep or loft (which will tend to end up with the "nearly smooth but not totally smooth" type problem). There's an example of that here, I'm not entirely sure if it applies directly to what you're trying to do but maybe:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1002.2

Do you have any photos of the keyboard that you're trying to model?

- Michael

Another area that looks like a problematic structure is this area here:



Those 3 surfaces look like they're flat to one another but when I removed them and tried to create one single large plane (which is better for filleting), it would not build it there, which means that you've likely got another one of those very shallow crease type shapes in that area. That's going to make it difficult for any fillet to work that has to go through that zone.

- Michael

Hi Michael,

thanks for looking into it. You helped me a lot with this one.
And yes, those were exactly the parts I wanted to fillet and which gave me headache.
I tried to get a little work around by rounding the curves before I`m using Sweep.
I´m not at a hundret percent know, but I´m quite happy with it because the model must not be perfect.

Here are some pictures of the original.







And here is my "final" result.



Cheers and all the best.

Holger

Hi Holger, it has turned out well!

- Michael