how to fit Rigid insulation on curve wall

I used bubble insulation for those areas. Would probably just kerf the back of the foam next time.

I put a few strips of aluminum HVAC tape on the back side of the rigid foam (the side that will lay against the plywood panel), flipped the foam over and made several slices about an inch or two apart from one edge to the other (similar to "curfing" a board so that it will bend). Don't cut through the tape on the other side though. Break the rigid foam at the slices (the tape on the back side will hold it all together).

The slices will allow it to bend around the curves.

I hope that explains it well enough. I can try to find some pictures if you'd like.

Depending on the radius of the curve, you may not have to do anything at all. Just apply gentle pressure when fitting it and it will probably form itself to the curve. I got 1.5" rigid foam to conform (mostly) to the approximately 20" radius in the roof corners of our Silver Dome. A few panels snapped on the outside (foil) face, but I just put some aluminium tape on the breaks and fit it back in. If you're having problems, kerfing as others suggested will work. I also used Reflectix on the front corners, but it's more expensive and not as good R value as rigid foam.