There are errors in my earlier explanation of these tools (sorry about that SuperSGL) and the following info should clear up a bunch of things. I've used these tools many times but never really thought much about how they worked since, for me anyway, they just did.
Anyway, after playing around a bit last night here's some stuff I learned about these tools and a quick demonstration of how to use them.
First install the menu scripts as described earlier...
...then download this project file...
mirrorSwapMiniDemo.moho
Open the file and you should see this...
This is an asymmetrical shape that's humanoid on the left side and feline on the right. There are the same number of points on either side of the shape.
First let's learn the Mirror Points tool. Select the top center point as shown above and then select the Mirror Points menu script. The result should be this...
Undo this so we get back to the original shape. Now select the bottom point and run Mirror Points. The result should look like this...
Some more info about Mirror Points:
1. As described in the beginning, the ideal shape should have the same number of points on either side.
2. Even though Mirror Points is supposed to work with Bezier points, it's not recommended. Chances are good that you will get some errors if you use Bezier points. (More on this in a future post.) If you must use Bezier points, you might want to wait until after running this script and then make those adjustments.
3. I
think the direction of the mirroring depends on the direction in which the shape was drawn and which point you choose as you axis. I'm not completely sure of the rules so TBD.
Now, how to use Swap Sides. Undo the 'cat head' so we're back to the original 'human-cat' shape.
Select the top center or bottom center point (it doesn't matter which) and choose Swap Sides. The result is this...
It may appear that Moho has merely flipped the drawing
but this is NOT what just happened. What actually happened is that Moho moved around the points on the left side to look like the right side of the head, and moved the points on the right side to look like the left side. This is why you need the same number of points on both sides of the shape.
So why would you ever need to do this? Well imagine the drawing is a left side head profile and you want it to animate smoothly into a drawing of a right side head profile. If you
flip the shape, the points will simply cross over in during animation and make a big mess in the middle. But when the points are moved around like when using this tool, the shape will transition smoothly and predictably, without crossing over.
Anyhoo, that's the concept behind these tools in a nutshell. There's more to using them in a real-world rigging situation so I've prepared a second tutorial that goes into greater detail. I'll post tutorial #2 tonight.