In Photoshop, is there a way to warp an irregular image selected area, but with controllable number of sides (let's say 8), by these boundary lines instead of a general rectangle around the selection (with help of Illustrator if necessary)?
I think you already know about Transform-> warp and it's not giving satisfying result.
Only similar option I remember is a Puppet warp
Quick guide: 1.Select layer 2.go to edit->Puppet warp (triangular grid will appear on the object) 3. Add several anchors to object by clicking 4. Click and drag to move the anchor and portion of object
When you exit Puppet warp tool, anchors are lost
Hope this will help. More info https://helpx.adobe.com/photoshop/using/warp-images-shapes-paths.html