SphMap input vectors lie on a unit sphere?


This is a boolean attribute which indicates whether the 3-dimensional vectors which are supplied as input to a SphMap are known to always have unit length, so that they lie on a unit sphere centred on the origin.

If this condition is true (indicated by setting UnitRadius non-zero), it implies that a CmpMap which is composed of a SphMap applied in the forward direction followed by a similar SphMap applied in the inverse direction may be simplified (e.g. by astSimplify) to become a UnitMap. This is because the input and output vectors will both have unit length and will therefore have the same coordinate values.

If UnitRadius is zero (the default), then although the output vector produced by the CmpMap (above) will still have unit length, the input vector may not have. This will, in general, change the coordinate values, so it prevents the pair of SphMaps being simplified.

Integer (boolean).


All SphMaps have this attribute.