I am new to graphic design and I am working on some figures for a paper. I want to use the isometric perspective and I have been drawing on the default axonometric grid with snapping. I want to put a rectangle down with rounded corners, but I cannot get it to sit right. When I got to document properties my grid parameters are 30 degrees in the x and z axis.
Draw a rounded rectangle on the grid.
Select the rectangle.
Set up the Skew Transform in the Transform panel, with the horizontal scew set to -60, and the vertical set to -30.
Apply the transform.
Reposition the shape to snap to the grid.
Note: after the transform, the height of the rectangle appears to double as it becomes stretched. So if you create your initial rectangle with half the required height, you should get the result you want. Or draw it at normal height, and apply a 50% scale transform on the vertical axis before you skew.
The nice thing about this method is that it works for any complex shape you care to make.