How to fillet the screw places in this rim model?

Hi guys,
I modeled a classic and conventional rim. All parts seem good else than its bolt places. I used Boolean tool to add those five bolt places but they need to be filleted in joints. Unfortunately, fillet fails in those areas. Can anyone please guide me and help me out to find out how to do so? I’ve provided the file as attachment. Thank you.
01.3dm (4.4 MB)

What fillet radius do you want?

Hi Alex - it looks like if you want a constant radius fillet, .07 will fit all the way around. FilletEdge does make the surfaces but does not trim them in correctly - you’ll need to clean up - probably because the series of edges is not quite tangent. Otherwise a series of FilletSrf with Extend=No will build the surfaces and you can trim them in.

WheelNutFillets_PG.3dm (327.3 KB)


Thank you Pascal,
Your file looks clean but I need a bit larger fillet. My problem is trimming. When I choose one separated fillet as cutting surface and the second separated fillet as surface to be cut, nothing happens. It cannot trim them. Actually I have trimming problem for surfaces like this. What is the procedure??

Hi Alex - if you want a constant radius fillet then .08 is your max - right here:


If you can use a variable, then you can get larger except in that area.


First of all, if you are going ti use filletSrf to connect the bolt holes to the rim then there is no point to using boolean. It just makes it harder to do the trimming and joining after making the fillets,

If you want to make larger fillets on the inner corner on the rim that your fillet has to cross over, you need to have a larger fillet in that comer. Also if you are making something that has fillets crossing fillets it is easiest to use true radius fillets. If you make true fillets crossing true fillets trimming and joining will generally work smoothly while filleting with blends crossing blends will generally be a nightmare to get clean boundary connections between surfaces. If trimming with the fillets used as cutter doesn’t work that’s almost always an indication of something wrong with the continuity of the underlying surfaces.

In the enclosed file I filleted and trimmed just one of the bolt holes and then you can use array polar to generate the rest and trim and join to finish the connection to the rim. I also replaced a blend with a true fillet (shown in red) to facilitate the trimming and joining.
rim.3dm (2.1 MB)


What is true radius fillet?
Can you please explain that how you created that fillet step by step?
Thank you.

It is a fillet with a true radius.
A lot of your rounded corners are not true arcs - they are blends. When making your profiles to be revolved, if you use true arcs (using curve fillet command) instead of blends that will increase the chances of success in trimming and joining when making crossing fillets.
The blends you used don’t cause problems where the overlapping fillets cross at around 90 degrees, but where the fillets cross at shallow angles that is where true radius will perform better. True arcs will also work better when the crossing fillet is close to the same radius as the curvature of the surface that its crossing.

I made the fillets with FillerSrf command (extend=no). Each fillet is made by clicking once on the 2 surfaces that the fillet will connect. The best location to make the 2 clicks for the next fillet is at (or near) the corners of the previous fillet. After going all the way around you can join the loop and then trim using the fillet loop as cutter and then join.

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I have used fillet curves command which has an icon in the ribbon. I tested continuity of the curves and they all were G1. I couldn’t get what you said. Can you explain the procedure more detailed? You were detached all those bolt nuts while I had booleaned it into the main body. Why???

Yes I see the rim body has true arcs but the boss for the bolt hole does not. That’s why I replace the one surface with the red fillet surface

Its easier and faster to fillet one and then after trimming and joining the fillets to that one use ArrayPolar to generate the rest.

I don’t know what more detail you need
Have you tried making the fillets with FilletSrf? Where are you getting stuck?

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I came to this conclusion that if I don’t use fillet in curves (curves of the areas around bolt nuts) I can use variable radius fillet so I can fillet nuts and all other areas that were left intact(without fillet in their curve section) and have a clean topology without need to any trimming, etc. afterwards.
Of course, there is an another solution and it’s Zbrush. I can export my model in to Zbrush and add a little bit smoothing around those bolt nuts.