Using Rand

[cspears2002]

point_instances.hipncI'm working on a tutorial out of the "The Magic of Houdini". At the object level, I have the following nodes: geo1, geo2, geo3, geo4, geo5. I'm going to assign the geometry in these nodes to points on a grid.

In order to do this I created a node called cloud at the object level. I jumped inside the node and layed down a Grid SOP and attached a Point SOP to the grid. In the Point SOP, I clicked on the Particle tab and added an instance. The script used to select the geometry for the instance is /obj/geo`int(rand($PT)*5)+1`

I can see how the script can select geo1. This would would happen if rand($PT) generated 0. However, isn't there a danger that the script would generate a geo6 if rand($PT) generated 1? This hasn't happened to any points on the grid. Is 0 <= results of rand < 1 ? I'm going to try to attach the file in question to this post.

[old school]

There is virtually no chance that rand() will generate a zero or a one.

If you are still concerned, you can always wrap the rand around a fit01() expression to tailor the results of rand(). Also look at the floor(), round(), int() expressions and other variants to cut down the upper range.