track a camera to an object with modifiers

i had this idea to track a camera to an object, then apply animation like forces (wind or turbulence) or even a soft body or wave modifiers to that object. some thing set up like this:

moving the cube gives some nice camera jitter possibilities. the problem im having is that all modifiers like waves and softbodies move the object, but not the camera.

are there any ways i can achieve this effect?

To track to you need the camera parented to a armature and track the armature to the cube.
To parent the camera to the cube make sure you click the camera before you click the cube. It should go where the cube goes. To track to it will only face the cube or look at the cube.

There’s maybe a bit of terminology confusion going on here. “Track To” is a specific kind of Constraint in Blender that makes an object (such as a Camera) point a specified axis at its target. This is good for keeping a camera pointed at a subject while it moves, but won’t move the camera itself.

What you seem to be talking about is more likely achieved using a Copy Location constraint. This is applied to the Camera and an object that can react to the forces you mention is made its target. When the target object moves, the camera will follow its motion as long as the constraint is fully enabled (its Influence = 1.0).

You could also use a Child of constraint of you need more kinds of control over the camera. Making the camera a child of the force-driven object (actual parenting) would also work but then there is no option to keyframe the Influence, which can be useful.

kind of. i think i may have worded that poorly :confused:

ive attatched the a blend folder with what im working on (blender 2.53). basically its a camera with a track to constraint, tracking to a cube. moving the cube changes the angle of the camera on its pivot point. i dont need it to change the location, just the angle.

if you play the animation, ive put a wave modifier on the cube, moving the cube up and down. i hoped this would move the cube, inturn changing the angle of the camera with it. so thats the effect im after.

track location, wont move the tracker with the tracked object under forces. it just changes the location. same effect occures with parenting. im looking to change the angle the camera views, like in the blend file, but through forces/modifiers on the tracked object.

thanks for helping :smiley:


camera.blend (362 KB)

You mentioned “camera jitter,” so I thought that meant something like camera shake, where the camera actually moves to produce the jittery image. You’re right that Copy Location, Child Of and parenting don’t change the way the camera points – that would need a Track To constraint, as mentioned. A common way to set this up is to specify the camera’s Z-axis with Y set for “Up” in the Track To constraint parameters. Then the camera will always point at its target. If you move the target under the influence of forces, or by keyframing, the camera should then track its motion.

I can’t load up 2.53 just now, so I’ll check the .blend later, but it sounds like you’re on the right track (pun intended :D)

I think what is going on is modifiers are sort of ‘temporary’ in that they work but they don’t permanently change anything unless applied. For example, a subsurf modifier adds more vertices to a mesh for viewing and rendering, but it doesn’t actually add more vertices, you can’t edit the extra vertices unless you apply the modifier. Another example would be to cut a cube in half, add a mirror modifier to it and you have what looks like a cube, but the 2nd half the cube isn’t real, doesn’t have editable geometry, until the modifier is applied. So I don’t think the method you are using will work, I’ll be interested to see what chipmasque comes up with and his opinion… as I could be wrong.

I have a method that will produce similar results thru using a f-curve modifier to change the curves for rotation of the camera. Blend file attached.


Edit: Blend file was too big to upload here on the forum, so it’s located at this link:

Good point – using modifiers to produce a motion may not create an actual movement of the target object’s center, which is what is tracked by the Track To constraint. In that case you’d have to use another method to transform the target.

I did some tests quite a while ago to check how a Cloth object reacts to gravity – at the time, I didn’t pay much attention to whether the Object was moving or just its verts. I’ll see if I can dig that up.

One way to get around this possible limitation is to use Vertex Parenting on the Track To target object. That way, if only the vertices move under modifier influence, the target will move with the parenting verts as well as with any object motion.

Here’s the basic idea: Some object is set in motion by using one of the forces or other modifiers. A vertex or set of three vertices is selected to act as a parent to the Track To target object (probably an Empty for this setup). The camera then follows the target object, which in turn is transformed by its parent vertices in the mesh under modifier influence.

EDIT: A quick test in 2.49b shows that a Cloth object falling through a Wind field does NOT have its object center diaplaced by either the Cloth sim reacting to gravity or the wind. So it seems you’ll have to use Vertex Parenting to have the camera follow the mesh deformations caused by the modifiers and fields/forces.

Further testing shows that camera tracking to a vertex-parented Empty works just fine.

Here is a soft body camera setup.


ras_sobft_body_camera_1c.blend (524 KB)