Blender Underground

As promised, here's my tutorial for animating a camera with a path and track-to constraint.


A fairly simple scene. I think it's the default scene (I've tweaked my defaults) with the addition of a path for the camera to follow and an empty for the camera to point at.


Go into the object buttons for the camera. You should find the constraints panel off to the right if you're using the default layout. In there, add the "Follow Path" constraint.



Set the constraint parameters as above (using the appropriate name for the path object): "OB", "CurveFollow", "Fw" and "Up". These settings make the camera point along the path (useful for simple flybys).

After making the above settings, you will probably find your camera to be slightly insane. Just clear it's rotation (alt-r), location (alt-g) and origin (alt-o). The camera will then be sitting on the path pointing along it.

Now for a bit more fun... making the camera look around: this is where the empty comes in.

First, add the "Track To" constraint (I've minimized my "Follow Path" constraint)

And then set the constraint's parameters as shown below (again, appropriate name for the empty): "OB", "Align", "To" and "Up".


The beauty of this setup, is you can control the orientation of the camera by moving and rotating the empty. If you don't want the camera's orientation to be affected by the empty's, turn off "Align".

Here is the blend file.

Because the camera was first setup to follow the path, you can now animate whether the camera points along the path or at the empty by playing with the camera's track-to constraint influence, which can be put on an ipo via the key button to the right of the influence bar. I've demonstrated this in the blend file. I also have the empty rotating to demonstrate its control over the camera's orientation.

Going further: it doesn't have to be a camera following the path. The object pointing at the empty can be a child of the object following the path. The target doesn't have to be an empty. Battle cruiser passing by a space station, turrets trained on the station . (this is probably where you'd want to turn of "Align", or not turn it on in the first place)

I hope that helps. If anything's not clear enough, or there are any other questions, please let me know.

Thanks!, I don't use this that much, and when I have to, I don't get it right the first times.

I'm keeping the file as a reference (tuning it a little to my needs) so I just can append it when i need it.

Very good tutorial. One note though. Anything set to follow a path will use the object origin as the point that follows the path. So for your camera, if the origin has been offset, the camera will be offset as well. All-in-all, a good tutorial...

Ah, yes, the object origin. I alway forget about it because it is so fundamental. However, I don't see a way to offset the origin of a camera.

Thanks for the feedback

The camera is a special object in that area. You can't move the origin without moving the camera but it still can be offset simply by moving the camera away from the path. You should see a dotted line going from the camera origin to the path when you do indicating the origin is what is following the path.

The reason I brought it up though is because any object can follow a path the same as your camera and the origin is an often forgotten pitfall for new users trying to animate on a path.

Nice tutorial taniwha! This is what i was able to do with it.

.blend

Edit:

Here is a zipped .blend

Thank you Taniwha, this will be a big help. How would I switch from the camera tracking one object to another?

walsh, you should be able to add two track-to constraints, each targeting a different object, and animate the "influence" slider in the constraint's properties.

This will come in mighty useful. Thanks for posting the tutorial.

ASE: nice. (first I'd heard of an E-wing. I haven't seen the prequels)


walshlg: as Apollos said. If you think about it, you'll realize that's what my blend already does: the first object the camera tracks in the path, the second is the empty. However, it seems the path constraint has very low priority over the camera's orientation.

LOL well I've got a constrained camera BUT my curve goes backwards. OOPs ==>> for everyone's edification it seems like the last point described when building the curve was the starting point of the path! Interesting.

So now I need help making a time IPO I think. Ummm what are the units? I'd love to be able to run the camera up and down my curve so I need to start out with time negative. I'm a bit confused about a time IPO

I'd also like to be able to run an empty up and down my vine's growth curve to track the camera to. Is the position on anything constrained to a curve dictated by a time IPO or is there another way to drag it along/ animate its position/ while keeping it still on the curve like we did with gnuren's growing vines?

If I change the length of the animation, say from 1-250 to 1-500 frames does everything move half as fast? If i animate from frames 250-500 does it start half way up the curve?

If it were easy, everybody would be doing it

Walsh, try going into edit mode and selecting Curve->Segments->Switch Direction.



Probably the best way to think of the time ipo is in terms of slope. Uphill (left to right) forward time; downhill (left to right) backward time. 2:1 slope = 2:1 time increase; 1:2 slope (one unit on x, two units on y) half time. Steeper the slope, the faster the time. Shallower, slower.

You can also check out this tutorial here for another perspective: http://blenderunderground.com/2008/02/0 ... -time-ipo/. It's not my best work, but it deals with the time ipo from the perspective of time remapping.



I honestly can't remember if it's the curve's time ipo that effects it, or the object that's following it. One or the other's time ipo will effect the speed that the object moves along the curve:
http://blenderunderground.com/2008/04/2 ... e-roundup/
http://blenderunderground.com/files/pos ... h_time.zip

Hope this helps...

thanks I'll give that a try tomorrow cuz time sure isn't seconds or frame number, sigh. Another interesting finding is that the path time from start to finish is 100 frames! I don't see where that is set other than in the animation duplivert window!

Use Pathlen in the Curves and Surfaces panel (Edit buttons). It can also be set with the speed Ipo.

anyone following this -> pathlen is set for the curve that is followed and is the time in frames that it takes to get from one end to the other.

also switch directions can be found in editmode/ curve