Day 03

Before I went home yesterday, I set up a simple setup to test collisions since I wasn't satisfied with the collisions I had with the steup I had yesterday.


                                                           Very Simple Initial Setup

                                                     The POP network of the first setup

I wanted the particles to seem "smart", as in they would avoid whatever obstacle that's in their way and still continue on course. I went around odforce and found a thread about crowd simulations. One of the forums users there "Deecue" posted a hip file with what I kind of wanted. The thread is here.

I referenced the method to get the particles to avoid some pillars I placed in the middle.


                                                            Added pillars in the middle

                                                            POP network of 2nd setup

 

I went to see the presentations made by Tanner, Jia Bao, Lu Sheng and Bryan on their SESI work. Great work by all of them!

After all of that, I went back with the collision setup i've been working with. I looked around about how to collide particles with other particles in houdini, turns out, you can't. I then went around to find out how to convert particles into geometry. I suddenly remembered about the copy node and used that after my pop network to map some simple primitives onto my particles. I made a switch to switch around between different primitives like spheres and boxes. I made a soft limit node in the pop network too, to kinda keep all the particles in the vicinity of the grid.


                                                         Added geometry onto particles

                                                            POP network of 3rd setup

I dug around my hard disk to find files with info on Houdini. Found a folder with various documents about Houdini shortcuts, extension lists, attributes and more importantly, commonly used variables in Houdini with definitions of what they do. The folder was from the Procedural effects class we had last year.  It sure came in handy, thanks Mr Ron!

I wanted to color the particles from the two different sources differently to see their movements clearly. I thought that it would be pretty simple to assign the particles into groups initially, but in the end, i could not put my head around it, it didn't work however I did it. So in the end, i settled with a pretty ghetto setup of using two pop networks and two switches. It'll suffice for now, i'll probably think of a way to make it neater. I also added an extra torus as an obstacle just to see what happens. The particles still move a little weird around the obstacles. I also don't really like how the particles advance, their not in a uniformed formation.


                                              My messy setup for colors and added obstacle

                                         One of the POP networks, both are exactly the same

 
                                                      Weird movements of the particles

I want to improve this system further so that the particles react to each other when they collide, I probably want them to randomly die on collision no matter which color they are. Right now I understand way more about the POP network and how the various POP operators work, compared to 2 days ago. I'll probably move on to understanding and researching other things after this.