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How to transform and distort the polar grid path in Illustrator tutorial. The grid can be transformed in a number of ways
1. By using the standard selection tools (all of the grid) as well as the direct selection tool to modify a selection of points
The grid can be modified by the scale and rotation and shear etc tools which can be found in the object menu and the transform commands. You can rotate and shear and reflect the artwork in numerous ways
You can also create distorted polar grids by using the free transform tool on the selected PG by using the effect menu and distort and free distort command. The tool hasn't been updated for years and years (though perhaps the underlying code has been changed but the functionality has not changed such as the size of the panel and also the range of the distortion). It is a live effect so you can modify the result via the appearance panel. You can also add additional free distorts to the PG along with other effects. See the result of a free transform tool transformation on the right
The grid can also be modified by the envelope distort tool (object menu) though the results are often less than impressive as the path is based on a stroke. You can use the make with warp (arc etc) as well as mesh warp where you use a rectangular grid to transform the path. You can also warp it using a top object (stars etc) via the make with top object command. See an example on the right
A totally radically approach would be to copy the path to Photoshop and use the transformation tools there (somehow I don't think that is very effective even if it is possible). There are other vector apps such as the Affinity Designer and Inkscape and you can use those to transform the generated PG paths.
You can also use tools such as pathscribe from Astute Graphics to manipulate the polar grid tool