After step 6, I am unable to follow the tut as it it makes no sense and makes references to options which I cannot find. Specifically Step 7 makes no sence, and I have no idea to what options they are reffering to. My feeling is that there are gaps in this tutotial. There is no '• change the Pass Through point Normals option in Point SOP.


'6. Append a Transform SOP the Convert SOP, toggle its display flag On and:
• change the value for the X translation to be a value of 20
• click on the channel button to associate an animation channel with the trans-late
parameters
• advance the frame pointer to frame 150
• set the X translation parameter to a value of -20
If dolly out on the scene and play back the animation at this point you will see the disk travel
along the X axis from positive 20 to negative 20 over a range of 150 frames.
7. Append a Point SOP after the Sort SOP, toggle its display flag On and:
(You should toggle the display of point normals on at this point)
• change the Pass Through point Normals option to Create Point Normals
• delete the current channel associated with the Point Normals A{
• enter a value of 15 into the first field (the Normal on X parameter)
• enter the following expressions into the Y and Z fields respectively
($BBY-0.5)*10 ($BBZ-0.5)*

This simply sets up the initial direction and velocity of the particles in a nice spray
pattern.
To create a more pronounced fan pattern to the spray you would simply increase the
multiplier value. ($BBY-0.5)*20 for example. But a value of 10 will be used here.
Note: Technically, you no longer have to manipulate the object’s point normals in order to provide the
particles with their initial direction and velocity. If you move into the Point SOPs Particle folder
you will notice there is now an option to apply velocity force to the particles directly, without
affecting the point normals on the surface. I like this technique though in that it allows you to tog-gle
the display of point normals on and visually see the direction of the initial particle thrust.
8. Toggle the display of the Point Normals Off once again.'

Dave Rindner

Hi David

hmm… odd that. The fact that it says that in the tutorial, not that you can't find it.
You are correct, the menu item you're looking for is called “Keep normal”.
Click on it and change it to “Add normal”. Now you'll see the three fields underneath it become active, and you should see some point normals displayed in the viewport. You can now add in the expressions and carry on.

Thanks for pointing out the discrepancy, I'll take a look tomorrow and get it fixed.

Cheers
marc