I have looked for and cannot find a trapezoid window family that can have variables for width, height, and slope on one side. I have tried to make one starting from an existing fixed window family and changing one side to an angle but I can't make it work properly. The width and height can be changed but the rise on the sloped side remains the same, even giving it a formula for the slope. I put in reference planes on the slope side and they change with the formula but when I align and lock the window to the sloped reference planes it is over constrained.