Path direction control

[Jeetman]

Hi all,

 

Can anyone tell me what determines the start of a path? I'm working on a SO shot and I have a crow constrained to a path that I had to modify by adding a few splines and now It's starting at the end of the path. I know I could use ease to make it work but I just want to understand how it works.

 

So what controls where the start of a path for a model is. I need to get the crow on the other end of the path spline.

 

George

[Rodney]

George,

I remember wondering that same thing many years ago. Problem is... I forgot what I discovered then.

 

I believe the general rule is: The first CP you place determines where the spline will begin. The second CP placement determines the orientation and direction of the spline (path) created. The end of the path that is modified last will be considered the last position.

 

Easy enough to test that theory.

 

Where things can get confusing is where you don't necessarily know which CP was created first or second.

Its easy to lose orientation in 3D space.

 

 

Edited the general rule to include Luuk's tip (see below).

[Rodney]

I've attached a basic test and project file to illustrate.

My CPs aren't showing up in this one but the numbers should help identify where they are.

 

All paths in this case are created in the same Model. Three splines/paths in all.

The spline/path on top was created left to right. Two CPs.

The spline/path under it was created right to left. Two CPs.

The bottom spline/path was created with three CPs... bottom left... top center... bottom right.

 

The arrows indicate the direction of the paths.

 

In each case the sphere follows the spline/path as in the order in which it was originally designed.

PathOfSpline000.mov

DirectionOfPath.prj

[Luuk Steitner]

The end of the path that is modified last will be considered the last position. If you need to reverse your path, a solution would be to add an extra CP to the end of the path and then delete that CP, so the path remains unchanged, besides it's direction.

[Rodney]

The end of the path that is modified last will be considered the last position. If you need to reverse your path, a solution would be to add an extra CP to the end of the path and then delete that CP, so the path remains unchanged, besides it's direction.

 

Ooooo... nice tip Luuk!

 

It should be noted that you must recreate your Path constraint after altering your Path.

(Unless I'm missing something else here)

 

To test this out I recommend dragging and dropping an object from your library... say... a sphere... or Thom onto a newly created path.

Go into Modeling mode (while still in the Chor) and Add... then Delete a spline at the end of the Path you want the Model to move toward. Delete the old Model as necessary.

Drag and Drop the model onto the path again... and you should see the Model follow the path in the opposite direction.

 

Thanks for the tip Luuk. I've added it to my collection.

[Jeetman]

Excellent help here!!!

 

Thank you Rodney and Luuk. This is really good to know!

 

George