I have a curve circle and I have a camera.
I select the cam and SHIFT-selected the path.
Then I hit CTRL-P and chose ‘Follow Path’ to make the cam follow the circle.
I moved the cam closer to the circle until the dotted black line nearly disappears.
This makes the cam follow the circle without any distance to the circle.
So far no problem, if I hit ALT-A then the cam follows the circle exactly.
Now I want to make the cam start from a different point on the circle.
But if I move the cam, the dotted line between cam and circle gets bigger and this is then the distance the cam moves along the circle.
So how can I change the start position of the cam on the circle?
The path animation system is a little weird I see… you can tweak animation in the curve object data panel, it’s the evaluation time property… if using a follow path constraint you have to manually animate the value, but you can also play with the contraint offset as Atom said. If using the traditional parenting method a modifier is assigned to the f-curve. Anyway if it’s just a circle simply rotate it
thanks for reply, but I used CTRL-P to add a ‘Follow Path’. I could not use a follow path constraint because it seems not to be working under 2.55.
I can add a ‘Follow path’ constraint but if I hit ALT-A to start the animation the cam does not move at all.
Therefore I used CTRL-P to create a path animation.
Liero: Can you explain more detailed how I must set / use Evaluation time to move my startpoint?
Constraints works but you have to manually animate a parameter in the curve.
Go to Path Animation tab in the curve and define total length of animation in frames. Pess ctrl+left to go to timeline start, type 1 in the Evaluation Time slider, hover it and press i to add a keyframe. Go to final frame of your animation, type it in the Evaluation Time slider, hover and press i. You can add more keyframes, make it go faster or backwards, but within the total frames range.
If you need to offset or repeat the animation you can add a cycles modifier to the animation track in the f-curve editor. You will find this stuff pressing n in the f-curve editor. The “Follow Path” method uses a modifier to animate your object without keyframes. If you remove the modifier you need to add keyframes.
Other tip, if you have parented the object press alt+o to reset its origin, or alt+g to reset position, so it lays on the curve. And yes, if the curve is a circle just rotate it.
I guess the point is that you can not “precede” the path in any way like other software packages do. A negative starting position for evaluation time. Yes, I can keyframe it, but Blender does not process it.
Let’s say it is not a circle, but is still a closed spline. Like the letter T. Assume the first point in the curve is in the upper left corner of the letter T. But I want my path animation to start in the lower right hand corner and loop all the way around. Blender can not do this, with out re-drawing the spline so the starting point is where I just described.
Basically there is no loop around for path animation. Blender can only go from start to finish. When it reaches the end it just stops. So in the above scenario, I could force the start point to the lower right hand part of the letter T (using offset or evaluation time), but it would never loop around.
Maybe the solution is to redefine the start point of a closed curve. Is that possible in Blender?
Or would a sawtooth f-curve for evaluation time do it?
Yes, within the defined frame range you can repeat and offset with a cycles f-curve modifier… and you can switch the curve direction but not easily set the first point.
Here is a way to do it… Using the curve modifier… I have put a prop on the cube.001 to allow you to change start loc and and velocity (both directions) of a red sphere. The property values can be keyed in…
Start Location 0.2 and velocity 0.1 will pretty much match the cube… Notice the jump on the corners, that is because the object has two vertices… I often use 2 to constrain a bone to one, and trackto the other. Delete one if you want it to follow the path exactly.
Custom properties and drivers are freaken’ excellent
Should have thought of this earlier… it’s the “best” way i’ve found of driving cars on paths.
Thanks will try that, but I found a way also with ‘Follow Path’ constraint, one has to enable ‘Fixed position’ then if one changes the Offset by clicking on the offset field and dragging the mouse in it one can see the object following the path.
Now one can set keyframes on different frames and offsets to start the cube on different positions.
But anyway I will take a look onto your solution sounds interesting as well!
