Hi,
Currently there are no specific curved options inside of PlusSpec, so unfortunately anything curved still needs to be manually drawn but we do have plans on adding these things in the future.
However, if you do wish to create a curved wall with the Wall Tool, you can draw a curve on the ground and then trace it with the Wall Tool.
If you’re interested, here is a link to a video on how to create curved or arc roofs that will estimate.
http://youtu.be/m_YXfYqPARg