Look At That!

Hi all.

My name is John Courte and I'm the senior Houdini Artist at Side Effects Software Los Angeles. I've been using Houdini and a lot of other stuff for a very long time, and now I have the opportunity to share that experience with you, the user community. Whether you're a seasoned Houdini vet (with scars), or a complete noob to CGI, I hope I can share with you some things that will make your days easier and get you home before you get that 'last person to leave the building' feeling.

First one is one I bumped into today, and that's camera lookats and dynamic objects. This is geared more towards a newer user, but i'll pose it as an option for the multi-year guru as well.

Handing off from Objects to DOPs happens in a number of ways, usually by animating something, then telling DOPs to make that something 'active' at a predetermined frame. Let's say you animated a car, and at frame 120, it gets hit by a train, flinging it across the Walmart parking lot and into the row of coin-op bouncy rides. You want to see this action from your camera, because a car going airborne and flying into a Walmart is awesome.

Easy. You just drag the path of the handoff (/obj/car) object from the tree-view into the lookat field of the camera. And then guess what? It doesn't work! The camera looks at the object until the handoff frame, then stops.

OK, well, you're smarter than the average bear, so you go "Aha!" Then you drag the RBD object in question from under /obj/AutoDopNetwork to the lookat field. This time, the camera doesn't even follow the car before the handoff.

This is where the gotcha happens. Instead of /obj/AutoDopNetwork/car, you need to make it /obj/AutoDopNetwork:car. That ONE little ascii character is the difference between simplicity incarnate and a long, drawn-out tea ceremony involving CHOPs, expressions, and a long night of rapidly graying hairs.

If you'd rather your camera just look at a real object, use a Fetch object and reference the dopobject, using the same syntax as the previous example in the lookat.

What if that's not an option, for some reason? Then you pull out the hammer. Create a rivet object and pick a point on /obj/car/dopimport1 or whatever you've called your dopimport SOP. Set the camera to look at the rivet object and you're done.