Particle meshes

I have one simple question. What is the difference between TriMesh and PointMesh particles? As far as I understand, PointMesh particles can use PointSprite mode in particles shader and are therefore faster, but are there any limitations to them? Can only TriMesh particles be rotated and used for sparks or can the same stuff be made also with PointMesh particles?

Point sprites are are not supported on all cards, which is why an alternative is needed.

Point sprites can be rotated. In fact they are automatically screen aligned.

Point sprites can’t be rotated. They are ALWAYS screen aligned. Don’t know if that was a typo but I thought a clarification was in order.