phys_thruster won't move in a straight line

I’m trying to configure a thruster connected to a physics object that can be reliably controlled via inputs. However, the thruster seems to randomly move the object left or right while pushing it forward, making it very difficult to control. I tried balancing it out with 2 thrusters on each side (at half power each), but that didn’t help in the slightest. The thruster is perfectly centered, and the prop_physics I’m using has a symmetrical model. Messing with the settings doesn’t seem to help either; the “Apply Torque” flag sounds like it won’t rotate the object and only push it straight if unchecked, but from experimentation, the flag seems to do nothing. If I uncheck “Ignore Mass”, the thruster barely works at all, even if I give a high value like 10000. I can’t just limit the physics prop to an axis, either, as I want it to rotate and still be able to move forward after, or even while it’s rotating.

I haven’t played with phys_thruster yet but might I suggest looking at the props collision model? It might be building it’s mass based on the collision model. Check if it’s symmetrical as well.

The model’s collision model was very simple, it was a cube with some changes in the front. I switched it to use a model with a perfect cube as its’ collision model, and got the same results. I also decided to change the thruster to use the “Ignore Mass” and set its’ force to 100000. This time, it moved just fine, but still randomly rotated around like it did before, even with the new model :pudge: