This might be a bit of a technicle question, but I have been unable to find any precise description on how the ‘Orientation’ attribute on particles work. How are it put together (internally), is it an axis/angle pair, quaternion or a matrix? It does’nt seem to make any difference on the result wether I multiply, add or subtract the orientation so I’m just curious if it’s me who have completely misunderstood the thing or it is a weird bug/feature of ICE.

Cheers
Jacob

The docs say that it is a rotation, which is an axis + angle.

To confirm, get Self.Orientation and try plugging it into various constant nodes. You can plug it into rotation, but not into a quaternion or matrix.

It looks like both addition and multiplication of rotations give the same result --- the composition of rotations (i.e. the effect of performing one rotation after the other).

When you think about it, it makes sense to set it up this way since addition and multiplication aren’t formally defined as they are for scalars, vectors, matrices, quaternions, etc. It brings rotations into line with matrices (multiplying two matrices that represent rotations gives the result of performing one after the other) as well as with the naive intuition that performing two rotations is “adding” them.