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fillets on a "cube"

davide ciarloni's picture

I would like to create fillets that are "eating" the involved face(s).
See my basic test on Draw
# make prism
polyline f 0 0 0 100 0 0 100 100 0 0 100 0 0 0 0
mkplane f f
prism p f 0 0 200
# make fillets
explode p e
blend b1 p 50 p_1 50 p_8

I noticed that I can fillet up to 49.9999...
Is there a way to do that or is it a known limitation?


Forum supervisor's picture

Dear Davide,
It is the known limitation, as one of the involved faces with the specified parameters (r1=50; r2=50) is fully disappeared from the result.

davide ciarloni's picture

many thanks supervisor for your prompt reply

Are you working on fillets?

Do you foresee improvements?
If Yes, when?


Forum supervisor's picture

Davide, most of improvements and new features in Open CASCADE Technology have been introduced in the framework of our Customers' projects. Therefore, if you have an industrial application and feel an urgent need in a particular improvement or a new functionality, please, consider becoming one of our Customers. For example via our A-la Carte Support services ( )
Forum Supervisor

davide ciarloni's picture

Thank you Supervisor

If you already worked on my case for other customers, can you please send me back the brep file?



Forum supervisor's picture

Davide, this part of Open CASCADE Technology has not been modified since the release of OCCT 6.5.1.

PG's picture

Hi Supervisor,

I have a similar problem which is bugging when most CAD systems give output on edge blends.

Try this out in OCC TH,

Draw[28]> circle c 0 0 0 25
Draw[29]> mkedge e c
Draw[31]> wire w e
Draw[33]> mkplane f w
Draw[34]> fit
Draw[35]> prism p f 0 0 10
Draw[36]> fit
Draw[37]> explode p e
p_1 p_2 p_3
Draw[42]> blend res p 5 p_2 5 p_3
tolerance ang : 0.01
tolerance 3d : 0.0001
tolerance 2d : 1.0000000000000001e-005
fleche : 0.001
tolblend 0.01 0.0001 1.0000000000000001e-005 0.001
Draw[44]> fit
Draw[45]> donly res
Draw[46]> fit
Draw[47]> blend res2 p 4.9999 p_2 4.9999 p_3

Is similar limitation in 2D edge filleting ( what is the API/Command )


- PG

Forum supervisor's picture

Hi PG,
It is limitation of the current implementation of the algorithm (as for 3d as for 2d cases). In the future we will try to remove this limitation.
API for 2d: BRepFilletAPI_MakeFillet2d.

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