Fillet Not Working


#1

I’m not able to fillet the top edges of the oblong cavities. The bolt cavities fillet, but there’s a discontinuity between the external fillet and the internal fillet against the wall. Two problems.tailpipe3.3dm (3.3 MB)


(Pascal Golay) #2

Hello - yeah, that is a bit of a nuisance if you want a .045 fillet - I’d take the trouble to build this the long way once and then ArrayOpolar to get the others.

  1. ExtractSrf the angled surface

  2. UtrimBorder

  3. ExtendSrf the top edge a little ways - enough to accomodate the fillet. .1 is enough, Type=Smooth.
    image

  4. FilletSrf from this surface to the hole cylinder.
    image

  5. Trim the top bit of the fillet that cuts into the large cylinder.
    image
    image

Trim and Join all the ‘local’ parts there and then replace the ones all around with these.

image

-Pascal


#3

There’s a couple steps in the cuts that cause the fillets in SW to fail.


#4

I’m aware of the steps, but it didn’t occur to me that that was the problem.

I created those pockets by differencing an extrusion I made from a curve. The original curve I made had no discontinuities. I did a polar array to create the other 5 curves and 4 of them had this discontinuity. Why???

Now that I have the discontinuity, how do I get rid of it? I can go back to the pre-extruded curve and smooth it there if there’s some kind of curve-smoothing process, but I don’t know what the process is, if any.


#5

It’s not The problem. It’s another problem. Go back and check your curves. There might be some stacked. There’s no reason why polar array would cause this discontinuity.


#6

You meed to start over - the error is in all the pockets

The best way to do this is forget about using solids to build this. Rhino is a powerful surface modeling tool. You will get done a lot faster if you work with surfaces and only arrive at a solid as the very last step in the process. As a bonus doing it with surfacing tools will give you a more accurate solid in the end.

The first step is make your revolve as loose un-joined surfaces. Then make one pocket and bolt hole as un-joined surfaces. Then do the filleting and trimming for one set. After you have one complete then array polar and trim and join (See file)

tailpipeX.3dm (1.6 MB)


#7

Thanks Jim, I’ll give it a try. I’ll probably have more questions before I get it done.


#8

Feel free to ask. I should have mentioned that you need to be very careful that curves (arcs) that you want to be concentric and tangent are precise. Tiny deviations will make the job much harder,