Rotating children, without parenting

Hey, i'm a wee bit stuck with how i would rotate particles round a certain point. For example:

My particle system is single surface so i can't parent the mesh to a pivot and rotate the pivot, because then all my particles would rotate around it. Any ideas?

You need Tformpoint to rotate the vert point around another point. Do it to all four points of a quad...

hi, thanks for your reply, but how do i specify how much rotation i want? I don't really get how the Tformpoint command works :(

From my own single surface particle system (source'll be released when I'm bored of it):

TFormVector -s\s,-s\s,0,camera,0 
VertexCoords s\surf,s\verti[0],s\x+TFormedX#(),s\y+TFormedY#(),s\z+TFormedZ#()

TFormVector s\s,-s\s,0,camera,0 
VertexCoords s\surf,s\verti[1],s\x+TFormedX#(),s\y+TFormedY#(),s\z+TFormedZ#()

TFormVector -s\s,s\s,0,camera,0 
VertexCoords s\surf,s\verti[2],s\x+TFormedX#(),s\y+TFormedY#(),s\z+TFormedZ#()

TFormVector s\s,s\s,0,camera,0 
VertexCoords s\surf,s\verti[3],s\x+TFormedX#(),s\y+TFormedY#(),s\z+TFormedZ#()

Whats interesting? well s is our scale! for a quad, it's even on all sides! the scale is tformed by the rotation in tformvector As you can see, they are tformed to the camera space..... ;)

Um....sorry for being kinda stupid, but how do a specify how muh rotation i want. Say i want to rotate my quad around 0,0,0 by 40 deg. Again, i appreciate your help, but as you can tell, i'm a wee bit clueless :)

This is a single surface particle: it always faces the camera. To rotate it a certain point from here, is exactly like rotating 4 pixels in 2D: you use our friends cos and sin.

x=x+cos(rotation)*dist
y=y+sin(rotation)*dist

Where dist is the amount between them. In our example above, thats s for scale.

You add it into the final equation - this will give results like rotatesprite - I am assuming you want that behaviour? because moving a bunch of verts is simplicity - you make the vert positions = pivot position.

Code archives has a single surface thing if you're interested.

Thanks for your help on this. The rotation i'm looking to do is the same as a sprite, ie. rotating all axis's. No doubt i'll be back here asking for help some :o)

One ideas i did have tho, was to create a mesh consisting of 1 quad, then rotate this quad to the desired rotation, then use it's vertex positions to position each quad. I think this might be a wee bit slower tho, as i'll need to rotate the quad into place for each particle.