Return a point on the curve at a point specified by t.

The function expects t to lie between 0 and 1; values outside the range are constrained to 0 and 1, respectively.

This function is not a counterpart to the line.pointAt() function. The relationship between t and distance along a curve is complex and non-linear. If a point at a certain ratio (normalized length) away from beginning of the curve is needed, use the curve.pointAt() function.