I was back at work last night writing code to handle special cases in the linkage simulator. It turns out that every type of connection is a special case, almost. Here is what I have working:

There is one case I can see that is missing but the mechanism is complex enough that the variety of special cases will be clear.

1. B slides on ef will move to match the position of B.
2. b slides on AB and ab will move to match the position of AB.
3. Link 1 slides on D and E even when D is moving.
4. Link 1 is slid by C that can slide between TU.

There are other elements to this mechanism but this shows how the sliding connectors add much more complexity to what had been a simple mechanism simulator. The reason that this is complex is because the analysis and geometry needed to simulate each of the different types of connections is unique to the type of connection. Take the connector C situation, for example. C could have been a simple connector and not a slider and it could have been connected to some other links that caused it to move left and right in the mechanism but could also float up and down freely. It would have moved link 1 in the same manner as it does now but finding where to move things would have required a circle-to-line intersection equation instead of a line-to-line intersection equation. The other sliding connectors cause the same types of variations in the code.

As before, you can get the simulator program here. The copy now available handles the mechanism shown as well as a few other variations. There are still a few special cases that are not handled. This won’t work:

This is another special case for sliding connectors. Link 1 and 2 both need to rotate so that the sliders D and E slide between A and C. This case needs to be detected and handled in a special way like most of the sliding connector situations. I hope to have this one working this week but other things are coming up.

Tomorrow night is welding class. I’m taking the Advanced Welding for Art class at TMCC for the third time. This might be the last time unless I am successful with my sculpture this semester. The last two were great but I rate my success by the end result as well as by the complexity and diversity of the work. Right now, I can’t think of a sculpture that would require some sort of new welding skill or would be different or interesting enough to show in a gallery.