Render Plus products are available for all SketchUp Products from SketchUp 8 through SketchUp 2018
See the IRender nXt - 3D Design Studio - ArielVision 2018 Release Overview for an overview of the great new updates included in the 2018 release of these products.
Your Render Plus License Status
You need to download and install your Render Plus software product for it to work with SketchUp 2018.
Please read the following to determine the status of your Render Plus Software license with regard to its use with SketchUp 2018:
If you have purchased or renewed your license in the past 12 months you can download the latest version and install it for use with SketchUp 2018. Download New Version
If your license is more than 12 months old you will need to renew your license before you can download the SketchUp 2018 compatible version. Renew License
If you have a SUBSCRIPTION license you can download the latest version of the software whenever you choose to move to SketchUp 2018.