i use archicad to figure how will look

[RSALVAREZ]

Hi, i was trying to add a closed cabin to my thunderbird 23, after draw and measure i was looking to import the photo of the boat and import a cabin
i try to build a 3d cabin in some cad programs and cant find an easy way to do , i search and find a demo of archicad
and was able to draw the cabin as a house walls with celing and windows i cant find curvs, was a good visualisation experiment
i have maxsurf,rhino,acad,gtworks,proyacht and i spent hours tryin to get a 3d view of my idea
there is any other option that work for the novice? thanks