Help with curved profile

[WillAdams (William Adams (Carbide 3D))]

Probably you would want to model the entire arc in two sections, then have intermediate geometry to flatten the middle with an Equals operation.

Alternately, is using a Roundover tool an option?

Using unsupported tooling in Carbide Create: Roundover / Cove / Radius bits

These are usually used in routers for decorative effects in wood: https://www.whitesiderouterbits.com/products/1570 but they are potentially useful for joinery: They are also useful for rounding off parts to allow rotary motion as for a hinged lid. Unfortunately, Carbide Create does not support this endmill geometry — but using the new support for previewing a V endmill when used in a No Offset Contour toolpath, it should be possible to preview them w/ confidence by stacking a series o…

(and that suggests using a succession of V tooling to approximate this)

If you have trouble, upload the file and someone will walk through this with you.