looping a free cam along a path

[and3x]

Hi, im totally new to this forum (cg forums in general for that matter). I am a cg-student living in sweden and i was hoping someone could help me out with a slight problem i have come across.

I am trying to animate a free camera along a path with pathconstraint in max 4. The camera follows the path just fine with follow and some amount of banking enabled. The problem occurs when the camera reaches a vertical "loop" in the path. When the camera is at 1/4 of the loop it flips about 180 degrees and then flips back at 3/4. It is as if it refuses to go "upside down".


Could someone please point me (and the camera) in the right direction.

take care // and3x

[Tim_Cutho]

you could try turning on (or off) the follow and bank settings in the path constraint, other than that I'm not really sure :roll:

[and3x]

Thanks for the reply, but i have tried that, and i need follow to be enabled in order to get the camera to run along the "tangent" (?) of the path. Otherwise the camera will face straight forward during the whole loop.

Any other ideas anyone?

Thanks in advance! // and3x

[dean]

I remember seeing a tutorial about animated tanks that covers the whole follow path problem. Unfortunately I'm not sure where it was. I will see if I can find the link for you.

Can anyone else point us to that tutorial? Look at the 3Dtotal site in Max tutorials, I'm almost sure it's listed in the animation section towards the bottom of the page.

[blesson2k]

It must be flipping over at both those vertex points along the path. try setting the vertex to smooth. I think that point's tangents are flipped over? did u try creating the path again?
But before that, set those two points to bezier and pull out the handles, and u'll know what I meant. u should see them turned the other way round. Just make them straight again by adjusting the bezier handles.:)

[and3x]

It does not seem to be the tangents, i just tried to draw another loop for testing purposes and i got the same result there aswell.



Here are two pictures that might explain things further. One is on frame 36 and is showing you the camera as i would like it to follow the path, and the other is on frame 37 where the camera suddenly has flipped over.

regards // and3x

[blesson2k]

enable the option Allow Upsidedown

[and3x]

Now, it seems that i was a little bit too exaggerated in the tex i wrote earlier (see below). It still flips. :(


I cant believe this is happening!!! It works alright, but i could have sworn that i really had tested checking that option a couple of hours ago, since it really seems to be the obvious solution, just by the name of that option!

[Ghori]

I don't know if this might work...

...have you tried animating a dummy object instead of a camera, then link the two...

[blesson2k]

If it still flips there must be something wrong. Delete the old path and create a new one and see if it works. But before that, create a simple scene and make a circular path and try animating the camera as before and see if it still flips. Sorry I didnt reply earlier as I didnt check this thread thinking ur problem was fixed.