Whats new in version 0.8?

I'm back in business! Had a little hard drive issue on the laptop I use to build and distribute, so I've been working on the code but hadn't been able to update the beta test release for a little while. Thats all resolved now though, and the updated version should be live in the next day or so. Four new load types are included:

• External Force
• Actuated Force
• External Moment
• Actuated Moment

The external forces and moments act on a single point or frame, respectively. You define the load magnitude as a string on the force or moment line in the dialog. This load can be a numeric constant, a parameter, or an equation containing a combination of numbers, parameters, generalized coordinates, generalized speeds, and Python operators. 

For an example, suppose you want to define a constant force of magnitude 100, applied to a point "a" with a vector aligned with the y-component of the inertial frame. That specification in the dialog would be:

• name = None (optional, feel free to give it a name)
• ref_frame_key = inertial
• ref_point_key = a
• force = 100
• x = 0
• y = 1
• z = 0

Alternately, suppose you wanted a time-varying force, you could specify

• force = 100*sin(10*t)

Above will give you a sinusoidal input. Supposing you want a state-dependent force, where you have a generalized coordinate q_A(t) that defines the vertical deflection, you could specify.

• force = - q_A**3

That will give a force equal to the displacement-cubed.

Actuated (or internal) forces are very similar. The difference is that these are applied with equal magnitude and opposite direction on two points or frames. 

Quite a bit of my work for the past month has been on reorganizing the back end to make it more stable and maintainable, if I've done it right that should be invisible to you, the user. Should help me with getting better and more frequent updates released. Hope to release on the app stores in the next couple of months!