Hi N2008,

Try adjust some render settings like:

Turn ON the "improved edges"

Set "Light Quality" to Good and "Accuracy" to 1 pixel.

To get a transparent background you will need to delete the plane and in the Render Room in the Output tab:

1 - choose a file format that support alpha like PSD

2 - turn on the options: Render Alpha Channel and Use Premulti´plied Alpha

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