View Full Version : Hard Dynamics Question

08-03-2005, 08:42 PM
I have a scene that has a number of objects and has a sphere that flies at the objects. I want to use hard dynamics to make the objects bounce away when the sphere hits them, but also be able to hit other objects in the scene. From what I've read it seems like this should be easy but I am having a hard time.

I added a "FX Collision" dynamic to the sphere. The first thing I tried was just adding a "Hard FX" dynamic to one object, but after I calculate the dynamics, in the first frame the object flies away before the sphere is anywhere near it. It seems to work when I set "exclusive collision" to the sphere, but I do not think that is what I want to do because I may want other objects to hit it too.

I also tried adding "FX Collision" to other objects, and I can only get the dynamics to work if specify which object is going to hit it (again with "exclusive collision").

What am I missing/forgetting to do?

(I'm new, so I hope this all makes sense)

08-04-2005, 01:12 AM
So, like a bowling ball hitting a pin and that pin hitting another and so on?

08-04-2005, 02:00 AM
but after I calculate the dynamics, in the first frame the object flies away

If you enable "start by collision" it should fix this. As it is now it sounds like you don't have that enabled, in which case the object will start to react to the collision object immediately rather than by contact.

08-04-2005, 10:39 AM
Be sure to turn on interaction in the Collision tab of Hard_FX. Unfortunately, you can only specify Sphere or Box as the interaction...it'd be nice if you could specify Node or Object here.

The FX_Collision objects are the effectors, the Hard_FX are the effectees. If you want your sphere to bounce off of something even though it's a Collision object, add Hard_FX to it as well so it's both an effector and an effectee.

Regarding the early/late effect of the collision object, you can adjust it's size in the FX Collision panel, even setting it slightly negative if necessary.

Here's a quick scene which might help.