not that Arnold is not, but you may want to get learning Arnold so you're not staying back in time. Mr and vray were quite fine for home int/ext rendering. Personally both this problem and the scene converter should have been nailed down and ready for primetime, which I don't feel they are both NOT. Not to mention the viewports working tightly with Arnold like mr did.

The Scene Converter in 2018 isn't quite perfect to go from mr to Arnold 'smoothly'. so you don't have to re-work all your past accumulated files like which has now happened with all the mr users. Unfortunately, if you want to use mental ray with Backburner to run a render farm, you will need to purchase licenses from NVIDIA.At this point, probably best to re-train yourself with Arnold or something you chose that you think may last a good while into the future. Note – the free license is good for a single stand-alone installation only, and does not include render-farm capabilities. The mental ray rendering plug in is available as a free download from NVIDIA and can be obtained here.

Good news – you can still use it in 3ds Max 2018! However, if you want to use the Lighting Analysis Assistant for 3ds Max, which is still included, you need to be using the mental ray engine. In fact, I’m finding the quality of the images, especially interior scenes, to be superior in many ways to what I could achieve with mental ray or ART. So I’ve spent the last few months getting up to speed on the Arnold engine, specifically for use in Revit to Max rendering workflows, and I’ve become much more comfortable with it than I was when 3ds Max 2018 was initially released. I’m the sort of person who tries to adapt to new technology whenever I can, and I don’t usually have much trouble leaving the past in the past. 3ds Max 2018 includes the Arnold 5.0 rendering engine, along with the Advanced Ray Trace (ART) renderer, and no longer includes the legacy mental ray renderer that so many people have been using for the last several years.

Nvidia mental ray 3ds max 2018 download