Pylon Observer solar design software is the best HelioScope alternative.
We have found that HelioScope is a fairly full-featured design software, but they are lacking a few features that make Pylon the #1 Solar Design Software in the world.
While HelioScope doesn't provide you with high resolution aerial imagery, Pylon includes imagery with resolution up to 5cm per pixel. Additionally, HelioScope charges you per month depending on how many users are on your team. Pylon proudly charges $0 Monthly Fees no matter how many team members you have. Pay a low $4 per project and avoid costly overheads.
Additionally, Pylon is different from most other solar design software in that the design surface is flat and in 2D but allows for 3D objects to be placed. This means that Pylon is perfectly suited for use on iPads as well as Desktops, and you don't lose any of the precision that you get with 3D shade modelling.