[Dilettante_Pro]

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>

<input name="mode" type="radio" value="значение 1">значение 1
<input name="mode" type="radio" value="значение 2">значение 2

Brush: <input name="brushPressure" type="text" class="form-control">
<script>
$("input[name=mode]").on("change", function() {
       $("input[name=brushPressure]").val(this.value);
});
</script>