The roller-coaster problem – a nice name for a problem you may encounter using motion paths in Maya. Named and explained by my Maya instructor Greg Berridge lately, I hereby note down the solution offered.
First, the problem: Draw a curve (using the EP or CV curve tool) which looks like a roller-coaster loop (hence the name) from the side view in Maya.
Now create an object which has a clear top/ down topology in order to see the problem you’re going to encounter (e.g. air-plane, not a simple ball/ sphere). Select the object and the curve and create a motion path (animate > motion paths > attach to motion path, default settings are fine). You may have to correct rotations of your object by selecting the curve and going into the motionPath1 tab of the attribute editor: tweak the front/ up axis/ inverse up etc. there if required.
Now play through the frames and all looks as expected – except one issue: the air-plane flips in the loop twice, which you definitely don’t want.
So, here’s the solution: create a second curve inside the first one. the easiest way is by just offsetting the first one: select the first curve, then Edit Curves > Offset > Offset Curve (be sure you deactivate “cut loop”). Here’s what you should get:
Now create a locator, select the new path and make a motion path again. Double check if the locator follows the path when playing through your frames. To finalise, select the air-plane and change world up type to “object up” and type in “locator1″ in the now editable field at world up object. The air-plane shouldn’t flip now any more.
This solution may help you to solve a lot of other troubles using motion paths. the more I dig into animation, the more I know: locators are the animator’s friends.
Hi Bastiaan. I was searching for maya motion path and found your blog.
Great idea to solve the flip on that loop example. I’m an animator, but I’m always practicing rigging in maya and 3dsmax, since I need to know that for my work and for myself. My question is this, can you help me find a solution in maya for this tutorial made in 3dsmax http://www.youtube.com/watch?v=9ae-SpmZ8RU
Basically, he adds that dummy to control the rotation of the car wheels. He attaches the dummy to the path and using the wire parameter he offsets the dummy in front of the arc path( which controls the skid on the back of the car). I’m having a hard time figuring how to achieve such thing in maya. Hope you read this. Bye
great post on the curve flipping – but a very important question is if you were using this practice for a roller coaster and flow pathed the carriages how do you parent the character to the carriage and maintaining – bank and follow – without having to add the character to the deformation – or is it better to rig the roller coaster apart from using the flow path style. ?
Man, you are awesome! and your instructor is brilliant too!
I was looking all over for the solution for this problem. Thanks a million. I'm a beginner Maya user, so I don't really know how to create a locator but I'll figure it out.
Thanks again.
BRILLIANT COLOSAL!!!!