Let's say I want to make a mark representing the shape of a rotor in a rotary engine:
This shape is similar to a Reuleaux triangle:
I know how to create equilateral polygons in Photoshop, but I do not know how to create curves that have the same curve handle (is that the right term?) on both ends.
How do I modify lines into curves and keep them symmetrical?
By the same token, how can I then make other lines symmetrical to the first line, especially when they are at odd (non-right-or-45° angles)?
In general, what is the best way to keep elements of shapes symmetrical when modifying them? Right now, I resort to lots of copying, pasting, flipping, and combining.
Note: I realize there are instructions on the Wiki-page for constructing a Reuleaux triangle using circles, but that only applies to an exact Reuleaux triangle where it is a curve of constant width. I am interested in creating a shape that may have shallower curves and is therefore no longer a curve of constant width. In addition, this is a principle I've run into more than once, so I'm interest in general principles for creating and working with symmetrical vector lines.