Lapping a path

I have a camera parented to a path. It zoomed around the path at 50 FPS but afther the 50th frame it stops. I actually want to control the amount of times it zooms around the path until the end of the number of frames that I setup to render. Is there a way to do that?

maybe your setup for “follow-path” uses a generated fcurve (a generator, thats a line-function …). Check this in the fcurve-window for the path/curve.
Then first delete it, because if you try to enter single keyframes to travel along the curve, you cannot create those keyframes with a generator as fcurve.
Then create the first keyframe at the start and create the last keyframe (one frame befor the object reaches the start again). In the fcurve-window for this animation enable a cyclic-modifier for this fcurve (made of 2 keyframes) and setup the count of cycles and you will see it will look like some zickzack-sawtooth-line …
instead of using the cyclic-modifier to do the repetition you can copy and paste/append the parts … … what would be the way if you need a different
animation at some parts …

edit: you may need to select a different interpretation of the fcurve-mode, there is constant, linear, bezier … etc. – linear may be the one you want to use.

I’ve deleted the generator, now the camera doesn’t move. What did I do wrong? I’m suppose to add a keyframe on the path, right? I added the keyframes and the camera doesn’t move at all.

did you notice i did make 2 keyframes? And did you notice at what frames and positions? …
What do you think if you enter only one keyframe … would this not be a still-frame, some kind of freezed animation?

I tried it again and I still think that I did something wrong.

maybe this picture tells you more than words
and if not, have i to upload the sample-blend-file for it?
I doubt it would help you, because there are a lot of tutorial videos
around showing how to insert keyframes … including the written
howtos. That may be the problem why i cannot understand the problem,
its nothing special to me (but this is it always with things after they are solved).

And what the fcurve shows, - i already did write it down in the postings above -
you may choose another evaluation-mode for the fcurve (linear, constant, bezier…) (check the meanings of those settings…or try the different results, then you may better understand).

Another point, you are speaking about “parenting” - this is not correct. You use a constraint-modifier (follow-path). To “parent” things together is only a way to describe the grouping of those and they can be grouped in different ways or you should limit the usage of this word to those settings like the setting of the “parent-entry” in the object-properties.



Here is how i have approached this one. The attached file uses a custom property “Loop” to drive the offset of the cube around a circle.
The driver

driver express ion = x - floor(x)
x = Object | Cube | '["Loop"]'

In the file i have keyed in Loop = 0 at frame 1 and Loop = 8.5 at frame 250 and the cube travels around the loop eight and a half times. (change to linear in graph editor for constant)


circuit.blend (77.8 KB)

Can’t get this blasted thing to work. All I got was this evaluation time that I can’t even edit and the line disappears once the generator modifer is gone in the Graph Editor.

There’s the file if you want to take a look.

pls. read again what i did post.
i did write down, that it is not possible to edit the fcurve for the “evaluation time” until you delete the generator in the driver setting for this fcurve.
You know how to switch from “fcurve” to the “driver”?
I have the bad feeling you dont know a lot of the basics about animations in blender and you may run into troubles without a basic knowledge.

batFingers sample is nice and very smart, but i suspect you wont get the smart way he is using the combination of object-properties with driver and usage of the math-floor to get the percent-position of the follow-path curve-length.

Check different video-tutorials and maybe you get the imagination about the basics.
The other way would only be (for me) to repeat again what i already did post.

So exactly where am I suppose to place the keyframes? Also what kind of keyframes am I placeing? Location, Rotation, Scale,etc.? Also, I do know how to animate. I just don’t mess with curves alot.

this proves i had the bad feeling …

i will try to guess what you did:

you created a circle-curve
you created an object(mesh)
you parented the object to the circle-curve with ctrl-p
and you did select the follow path option (and you dont know what this creates)

What keyframes to insert? One approach (this is only one!!) is to insert keyframes
for the evaluation-timevalue of the curve.
For this, select the curve and select the curve-object-data (the curve-symbol in the properties…you know?)
there you will see the green coloured button “evaluation-time”.
And that is the place to put the keyframes for the timing to move an object along the curve-path.
But you cannot enter a keyframe there if you try to use the “right-mouse-click” there (over this button) and select “insert keyframe” – it shows an Error-message about the usage of a generator-driver and with this, it is not possible to enter keyframes!
You open the fcurve-window (graph-editor) and see the fcurve for the curve-circle and its a straight line … (no keyframes … ). You may have to click on the bezierCircle to the “Evaluation Time” entry too.
Now delete the whole entry for the circle and then the “green entry-filed” of the circle for evaluation-time will lose its green color … and now you can enter a keyframe into this field.
If you enter the first keyframe, then you will see it creates a straight line, parallel to the x-axis in the graph-editor and it will again named as evaluation time (for the circle).
Now you have to enter a second keyframe … at what position?
For example, go to frame 100 in the timeland … just a click
and the evaluation time button will go to green color again.
Enter in the evaluation time button-field the value 100
and make a new keyframe (right-mouse-click and select insert keyframe)
and you will see 2 keyframes in the graph-editor …
Now you can edit this curve like you want …

Your keying in the evaluation time of the curve. You have chosen 50 as the number of frames for one cycle. It wont recognise any keys above this. As testo mentioned you need to delete the generator modifier on the fcurve.

Now you can key in the evaluation time. Key in 1 at frame 1 and 50 at 50. Make it linear, then add a cycles modifier to make the sawtooth pattern… I’ve attached the modified file. (keyed in frame 49 should be 50)

Another way to do this is with drivers. You can type simple expressions straight into the evaluation time property field prepended with a hash #. For this example typing

#frame % 50

Does exactly what we want. % is modulus, ie the remainder after dividing by 50… oh look i’ll attach another file to show how simple this method is… once again i stuffed up… the eval time of the curve should be 50 not 49… couldn’t be f’d uploading again… you get the idea.

It’ s really not all that difficult to set up this way. The main benefit IMO is not being parented to a single path.


Motion Path.blend (395 KB)MP_simple_driver.blend (396 KB)