This is just a quick start guide on what needs to be done in order to bring in your own URDF robot into UE4 using URoboSim.

Bringing the robot into UE4

1. Convert all your .stl and .dae files into .fbx.
2. Make sure there is a folder called "XML" in the same directory as your Unreal Engine Project File.
3. Make sure that you also have a "Plugins" folder here within which you have the URoboSim folder.
4. If your robot uses meshes, it will likely be inside a folder, drag this entire folder into XML (file structure must be unchanged if meshes are being used).
5. After the project is started, go to Edit->Plugins and make sure the plugin is enabled.
6. Drag the robot's URDF into the content browser (may need to wait a few seconds).
7. Drag the robot into the game world (again may take a few seconds).

Tuning parameters

8. Most likely you will want to make sure physics substepping is enabled. (Edit->Project Settings->Engine->Physics->Framerate, enable Substepping and see what Max Substep Delta Time works best, will probably want the lowest and you can probably leave Max Substeps unchanged).
9. Next if you notice some crazy physics behavior as soon as the game starts, this is likely caused by some meshes colliding with each other. Click on your robot inside the World Outliner window, then click on Details. You can see all the Links that make your robot under the Map category and also the full structure of the robot underneath Add Component. Once you have an idea of which links might be causing trouble, you can include them in the Collision Filter in the URoboSimEd tab (part of the Modes window). After clicking "Save Collision Filter", again drag your robot from the Content Browser into the world and see if the issue is resolved.