After the dozer, I now added a digger as well. It's already pretty convincing I think. Although it does have some difficulties with boulders getting stuck between the jaws, and then suddenly and violently get expelled from the bucket. Movements are jerky, mainly because the app would not sync to the 60fps display. Even though I used glfwSwapInterval() to make it sync. Maybe it is a GLFW3 bug.