cs00bren Posted February 24, 2003 Share Posted February 24, 2003 hello there i got a question about rotating normals. i'm using a particles system to instance a geometry on it the question is can i rotate the instances so that they don't points the same way. do i have to do this in pops or in sop. cheers bren Quote Link to comment Share on other sites More sharing options...
Marc Posted February 24, 2003 Share Posted February 24, 2003 This is a matter of great confusion and discussion. Houdini handles copying and instancing in totally different ways. Copying (ie using the copy SOP) uses the normals and the velocity vector to align the copy. Whereas instancing uses the rot attribute. The difference is that the rot attribute is a quaternion rotation while the other copy sop method is an euler rotation. Although, having said that I'm pretty sure thats still slightly off the mark (hence the confusion part. Everyone has a slightly different answer ) So, to answer your question. The easiest way to change the instancing is to use the rotation pop (try putting $ID * 20 into the angle setting). Putting some sort of random value into the axes will make it change on more than one axis. Hope this helps. Marc Quote Link to comment Share on other sites More sharing options...
cs00bren Posted February 27, 2003 Author Share Posted February 27, 2003 cheers i had tryed the rotation pop but i tryed using the expressions you said and it worked cheers bren. Quote Link to comment Share on other sites More sharing options...
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