I use blender, Blender has multiple VPLs that each specialize in one area. Texture, Material and Compositor. Blender VPLs are fully upgradable with Python code

I use blender, Blender has multiple VPLs that each specialize in one area. Texture, Material and Compositor. Blender VPLs are fully upgradable with Python code that allows the creation of new nodes . This allowed developers to create new VPLs using animation and modeling nodes. So even though Blender VPLs are not meant to be used as generic languages however there is already the API in place to allow this essentially exposing the entire Python scripting interface as nodes. Reaktor I do not know if it supports 3d physics particles , but you could do what you ask for from blender. Blender supports midi for controlling animation. Blueprints on the other hand are a generic VPL and can do anything you describe. It's also the best choice because Unreal excels at real time graphics.