text field triggered by radio buttion

Be aware that just hiding the field does not clear its value, so if you plan on exporting the form data to another format (and even if you're not, it's just good practice) it's recommended to not just hide the field, but actually clear it.

To do so you can use this code as its custom calculation script:

if (this.getField("group1").valueAsString=="other") {
	event.value = "";
	event.target.display = display.hidden;
} else event.target.display = display.visible;

You will find the answer here:

https://www.pdfscripting.com/public/Hiding-and-Showing-Form-Fields.cfm?sd=40

The simple way to do this is to use the MouseUp event on a radio button. You'll need to put code on every radio button that affects the visibility of the field. 

Enter the following custom calculation script in the text field:

this.getField("group1").value=="other"?event.target.display=display.visible:event.target.display=display.hidden;