Fillet size script

I’ve really been pushing our engineering department to think DFM (designing for manufacturability) and one of the issues that surfaces repeatedly is the fillet sizes used on a model. The smaller the inside fillet, the smaller the tool required to machine it, so up go the costs. I find myself constantly checking fillet sizes to see if we can make them bigger, or just go sharp to utilize an endmill. Currently if the fillet has a square edge I just use the Radius command and pick the edge. But when the fillet looks like this it requires extra steps:

Has anyone written a script that allows them to just pick on the surface and it returns the radius at the command line? I think that’s what I need to make this easier.



Maybe this?

Hi Gijs,

I’ll take a look, but I already wrote one. It was way easier than I thought it would be.



wouldn’t it be possible to just automatically check all your surfaces without clicking on them?

Probably, but I’m only concerned with certain areas.

Hi Dan

If you can automated just checking all faces for small radii…it would be the beginning of a QA tool to check models against.

If there are things you “always check” that can be (semi) automated you can save yourself much time.


Hi Dan, nice to meet you here sometimes. :slight_smile:

Not exactly on the command line.
This one draws a temporary dot showing the radius value.
It requires an extra click to delete the dot.
But you might edit it to get the output you need, if you like :slight_smile:

The script checks isocurves, so these curves has to be perpendicular to the fillet axis …
This is true for regular fillets built by Rhino.
( I use the script every day )

Anyway, here it is: (3.8 KB)

I hope it helps :slight_smile: .


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Hmm, slower than Emilio here - :stuck_out_tongue_winking_eye:

Here’s mine @DanBayn - just click on the surface or a subsurface in a polysurface and the radius is printed to the command line. You can surely polish it a bit for your needs.

Edit - forgot the last line. Plus, I added a tolerance value, might make it not so strict…
Edit 2 - had to make the picking tolerance less strict as well… :sweat_smile: (1.0 KB)

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Hi @Gijs, @Willem, @emilio, @Helvetosaur,

I appreciate everyone’s contribution. I will look at everyone’s suggestions and scripts, and I’m pretty confident that I’m going to have the exact solution I need.

This community is one of the best aspects of being a Rhino user. I’ve been getting this kind of help for 18 years. It’s hard to express enough gratitude to you guys for all the help you’ve so generously offered over the years.

Have a great weekend everyone,



Hahaha …

Eh … the advantage of being retired … taking things more slowly … :wink: :smile:

Ciao Mitch !

Definitely the best, in my opinion. :slight_smile:

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