making fillets

I have used fillet making function "BRepFilletAPI_MakeFillet" for some time now and it seems that there are many instances it fails to create a fillet. Can anybody comment on the reliability of this function?
For example, I have attached a Brep file here and am unable to put a fillet in the common edge. Is there something wrong with my shape or is it a shortcoming of the makefillet function that I can't make a fillet there? How can I fix this?

Thanks in advance.

Attachments: 
Forum supervisor's picture

Dear Chanaka,
As I see your model is very small.
Bounding box is : DX=0.0545873 mm, DY=0.05459825 mm, DZ=0.0299319 mm.
Could you specify value of the used radius of the fillet?
Regards

Chanaka Mallikarachchi's picture

Dear Forum Supervisor,
The model dimensions are actually in meters. It has not been converted to proper units when writing out the brep file. Basically DX would be 54.5873 mm actually. I have tried fillets with radius of 1 mm to 5 mm without success.

Thanks,

Chanaka.

Forum supervisor's picture

Dear Chanaka,
I have checked your case on OCCT6.5.1 (win32 model).
I got a resulting shape in some close limits of radius value: from 0.0009 till 0.0015 .
See the attached file (brep model). The post-fix means value of the used radius.
Regards

Attachments: 
Chanaka Mallikarachchi's picture

Dear Forum Supervisor,
Thank you very much for the input. I am still using OCC version 6.5.0. May be I should upgrade to version 6.5.1. Is there an improvement in fillet process between the two versions?

Forum supervisor's picture

Dear Chanaka,
You may look through modifications at Release Notes of ver.6.5.1.
But OCCT 6.5.0 gives the same results for your test case (wit rad = 0.0009 - 0.0015)
as OCCT6.5.1.
It works. Below is the script to check it in Draw.

pload ALL
restore toFillet.brep t
checkshape t
explode t E
fillet res t 0.001 t_3; ## gives Compound containing one Shell
checkshape res

Regards