Grooves in Arch using Sweep Void??

[Sarah Ashraf]

Could anyone help Please;
i'm trying to create a grooves along the arch using sweep voids, it has been done correctly in the straight legs of the arch but it couldn't be done in the arch, as shown in the Revit file attached....i need to know how to start and if its a matter of using the correct work plane and how to select the work plane of the inner side of the arch? or there is something else i'm missing..
Thanks :)

[irneb]

Firstly, try to offset your sweep path from the direct face of the host (I've chosen 2mm). Then make the profile a bit larger than you need (I've chosen to move the long side of the triangle by 5mm outwards). Then make the path a bit longer than the host as well - needs to be around 10mm longer than needed for curved faces (depends on radius).

Attached seems to work.