BEPUphysics

So, the only dynamic objects in my game are the boxes that you move through the level, and the rest of the objects are kinematic. Unfortunately, this means the boxes have a tendancy to clip through the kinematics, especially when the kinematics are moving the boxes through pushing them (which is almost all of them). I tried increased the boxes' mass to an ungodly huge number (int.MaxValue - 1, to be exact) because I remember you saying an object with a large mass depending on one with a small mass makes collision squishy, but it only slightly improved the issue.

Is there something else I could use besides kinematic enities? For example, could I make them dynamic but not affected by gravity and still have them not move when colliding with boxes (either without extra code or perhaps with a very rigid constraint)? Then I could set their mass to, like, ten, and the boxes to one, and that wouldn't be squishy (I might have to do some things with collision groups to keep them from responding from unlikely collision with each other, though). Anyways, any other ideas? Thanks!

Norbo wrote: However, the issue of kinematics crushing dynamic objects is different.

Norbo wrote: There are a variety of ways to make the machinery dynamic. The most obvious and direct option is to actually make them real contraptions bound together with motors and other constraints with specific motor strengths. Collision rules would indeed be useful for managing interactions. The RobotArmDemo shows the configuration of a complex articulated structure with constraints and collision rules.

Norbo wrote:for things where you don't need or desire physical weakness, kinematics are still a good thing to use. Faking things may also be useful sometimes (e.g. a 'pushing volume' as opposed to 100 individually rotating, motor-controlled rollers).

Well, the problem is that I don't need nor desire physical weakness, but not infinite mass.

I'm not sure what you mean by "pushing volume," is it, like, an invisible entity that pushes the objects in lieu of rotating rollers?

Unfortunately, transitioning from QuaternionSlerpCurves to motors isn't easy, so I thought I'd keep things as they were and instead just make motors that constrict the entities when they're stationary. This, however, causes problems with setting and unsetting the activity of the motors at the right times. Can you recommend anything?

Using motors exclusively as a movement device, the machine slows down as it reaches the goal and never exactly gets there.

Also, I can't find a way to make the motors strong enough to resist pushing by the boxes but not strong enough to crush them... What was the mass ratio at which collision becomes squishy?

            //Make an immobile barrier for a platform to rise into, attempting to crush a poor box.
            Box ceiling = new Box(new Vector3(0, 20, 0), 50, 1, 50);
            Space.Add(ceiling);

            //Create a platform to drop another box onto.  This platform will move up, eventually smashing into the ceiling.
            Box movingPlatform = new Box(new Vector3(0, 0, 0), 5, 1, 5, 10);
            Space.Add(movingPlatform);

            var angularMotor = new SingleEntityAngularMotor(movingPlatform);
            //This defaults to velocity motor.  Switch it to servo to keep the orientation steady.
            //(Could also set the inertia tensor inverse to zeros for the purposes of this demo.)
            angularMotor.Settings.Mode = MotorMode.Servomechanism;
            Space.Add(angularMotor);

            var linearMotor = new SingleEntityLinearMotor(movingPlatform, movingPlatform.Position);
            //This motor propels the moving platform ceilingward.
            linearMotor.Settings.VelocityMotor.GoalVelocity = new Vector3(0, 2, 0);
            Space.Add(linearMotor);


            //Drop this box onto the moving platform.
            Box freeBox = new Box(new Vector3(0, 10, 0), 1, 1, 1, 10);
            Space.Add(freeBox);

            //Make an immobile barrier for a platform to rise into, attempting to crush a poor box.
            Box ceiling = new Box(new Vector3(0, 20, 0), 50, 1, 50);
            Space.Add(ceiling);

            //Create a platform to drop another box onto.  This platform will move up, eventually smashing into the ceiling.
            //Note the low mass.
            Box movingPlatform = new Box(new Vector3(0, 0, 0), 5, 1, 5, .1f);
            Space.Add(movingPlatform);

            var angularMotor = new SingleEntityAngularMotor(movingPlatform);
            //This defaults to velocity motor.  Switch it to servo to keep the orientation steady.
            //(Could also set the inertia tensor inverse to zeros for the purposes of this demo.)
            angularMotor.Settings.Mode = MotorMode.Servomechanism;
            Space.Add(angularMotor);

            var linearMotor = new SingleEntityLinearMotor(movingPlatform, movingPlatform.Position);
            //This motor propels the moving platform ceilingward.
            linearMotor.Settings.VelocityMotor.GoalVelocity = new Vector3(0, 2, 0);
            //Weaken the constraint.
            linearMotor.Settings.VelocityMotor.Softness *= 100;
            Space.Add(linearMotor);


            //Drop this box onto the moving platform.
            //Note the low mass.
            Box freeBox = new Box(new Vector3(0, 10, 0), 1, 1, 1, .1f);
            Space.Add(freeBox);

Norbo wrote:Noted and fixed for the next versiong.