Saturday, February 21, 2015

Unreal Engine Experiment #1: Gravity Gun

A few weeks back, on one fine saturday, I decided to take some time off from my main project and do a small side project. I decided to do something using Blueprints that I could wrap up within a few hours. The plan was to then put the source in GitHub so that anyone else interested in it could build on top of it. Since I've been watching some of the 'Spoiler Warning' Half Life 2 episodes around that time, I was kind of all excited about the game once again. Probably because of that, there was only one thing that I wanted to make: a Gravity Gun. But I knew that it needed physics, and I haven't done shit with physics in UE4. So I did some R&D on the basics, and came upon a tutorial by Epic's T.J. Ballard in the Unreal Wiki, for lifting objects and such. Here's the link for the tutorial:

Unreal Wiki: Pick Up Physics Object Tutorial


Most of the building blocks that I needed for the project, were already laid down in this tutorial. I went through it, studied what did what, and luckily he had explained everything quite well. I just made some changes to it, in order to reflect the primary and second fire of the Gravity Gun from Half Life 2.



Within a few hours, it was well and working, except for too much momentum and rotation calculation issues for the physics object. Increasing the mass of the meshes fixed the momentum issue, but the rotation issue would require more work. But I got the basic functionality working. Here's a video of it running in the editor:


It's still not complete. As I mentioned, it's still got some issues with physics calculations. About a week back or so, I uploaded the source code into GitHub. It's available as free download for anyone interested in it. So anyone wanting to check it out or fix it up and use in their projects, can get it from here:

GitHub: Unreal Engine 4 Gravity Gun Experiment

Alright, that's all for now. Feel free to ask in the comments, if you've got any doubts regarding it's implementation.