Can't seem to get a correct flat pattern

[patrykstolinski]

Hello,

So I'm trying to flatten out the mantle that has a slight dip in the middle (photo included). I've tried flat pattern and unfold and they all produce the same result that I can't seem to fix.

Can I somehow force inventor to just make it all flat? It seems like inventor judges an orientation it should follow and when something doesn't, it ignores it.

Any advice appreciated, files included in post.

[JDMather]

Did you Attach the correct file here?

The file that you Attached does not look like your images?

In the file that you did Attach -

Sketch1 is not fully defined?

Angled lines are missing Tangent constraints to circles (and are overlapping).

Horizontal line is missing a Tangent constraint on one side.

Construction technique from there on does not make logical sense?

Sheet metal tools not used?

No Rip in the file that you Attached?

[johnsonshiue]

Hi! Indeed, the flat pattern issue here is due to lack of tangent constraints. The straight segment is not tangent to the circle. Inventor is a precise modeler. The geometry has to be as tight as possible. After adding the three missing tangent constraints (two at the top and one at the bottom), the flat pattern will work correctly.

Many thanks!