Hey everyone!
I have a question about the game engine. Is there a way to make alter a dynamic object so that it can only collide with non-dynamic objects, but passes through other dynamic objects? If this is impossible, I've made a simulation of a marbal passing through a LOOOOOOOOOOOOOOOOONG tube but I can't get the camera to follow directly behind it. Does anyone have any ideas on what I should do? PLEASE HELP ME!!!

I'd like to help but I don't fully understand the question.

If you want the camera to stay inside the tube without using python then you're in trouble. The camera does not collide with objects. And the camera actuator does not take collision into account.

Well... that really bites ! Does anyone know where I can find a python script or alternate method that will make the camera follow the marbal INSIDE the tube?

possibly the ghost button in the dyn object panel? or try turning off collision for the faces maybe?

Send me the file, and I'll take a look at it.

Ok, the file should be there by the time you read this. Thanks

Your file is pretty much okay

But,..... there are a few remarks.

In the game engine polygons are single sided, this means the camera sees them only from 1 side. You can make them double sided (this doubles the polycount) or let them all face inward. To do this you select the object and type TAB - A - Ctrl/Shift/N - Enter - TAB. For this to work (and that brings me to point 2) you need a nice and clean model.
Not only does this game engine not like many polygons, it really does not like many objects. So join your objects into one. (select objects, Ctrl/J - Enter).
Now how do you know in object or editmode what way the normal is facing? In the edit button-window (F9) there is a "Double Sided" toggle button on the right, depress it to see single sided polygons.
And while you're at it, also remove doubles, this is done in editmode with all verteces selected where you want the doubles removed from (in your case all , so TAB - A -> remove doubles - TAB.
An other thing you can do to see the normals direction is select the object and press F, now you're in faceselect mode, wich brings me to the next point ... I think you should add some lights (SPACE->Add->Lamp) and make all faces calculate realtime light. You can do this by selecting your object, go in face select mode (F) select all faces (A or A - A if one face was selected) and use the special menu ( W ) to set light ( W 3). If your in wireframe mode press Alt/Z to see the effects the lights are having on your objects, move (G) the lights for realtime editing. For extra tasty colors you can vertex-paint them in. Press the little paintbrush icon and you'll see face & vertex paint settings for your object.
Press V to go into vertex paint mode, and by pressing the leftmousebutton you'll paint the righthand color onto your object.

Have fun!

Thanks for those great tips ! They will come in handy. But how do I solve my camera problem?

What do you mean? The camera works fine.
It follows the ball inside the tube.

Sorry about my lack of clarity . What I mean is that the camera should follow the marbal like it would if it was parented but still follow inside the tube. Thanx for your trouble .

I don't know the game engine... but....
could you parent the camera to a cube or something that is behind the camera and then have the cube be the object that follows the marble... this would then allow you to have the cube take collisions and such and cause it to stay in the tube? don't know.. .never messed with the game engine much yet.

okay a question on those faces. taking into acount ONLY the speed of game and the file size which is better, textures or painting...(i hope i don't start something )

Painting will produce a smaller file, than texturing.

It shouldn't run any faster unless it is on a system doing the opengl in software (without a reasonable video card).

That said, texures can be pretty small, and add a lot when used properly.

Pablosbrain wrote:

I don't know the game engine... but.... could you parent the camera to a cube or something that is behind the camera and then have the cube be the object that follows the marble... this would then allow you to have the cube take collisions and such and cause it to stay in the tube? don't know.. .never messed with the game engine much yet.

I was thinking the same thing. Just need to make sure that the camera object is a constant distance from the marble.