Lumion BMP export problem


I’ve made my model in rhino and I was planning to run it through the lumion to have a nice render. Everything is beautiful in the normal resolution (jpg) but when I try to use a resolution (only bmp format available) the shadowed area come out as in the picture

Does anyone have an idea why?

Thank you

I haven’t heard of this before… I’d suggest trying the Lumion forum too if you haven’t already.