I'm working on a tool that is both a gamemaker and a demomaker (a realtime animation editor/player).
It use a procedural nodal workflow to create and connect visual bricks ("operators") used to make complete 3d animated scenes from generating textures and meshes to post-processing and clip sequencing. (see original concept : http://pcg.wikidot.com/pcg-software:werkkzeug)
It's a cross platform project using Qt for the editor GUI. The nodal system and editor is based on the enigma studio code (a nice demotool released by Brain Control, a demomakers group see: https://www.braincontrol.org/). Orginally it has an homemade engine based on dx11, that I replaced by Urho3D.
The project is at earlier step, but the editor and the nodal system is almost fully functionnal, I ported it on linux and fix it to work with urho.
The main work is to fix the editor and internal system to work with urho, build new nodals operators with Urho features and to build a player to replay scenes or play generated games.