Object visibility before and after spline when using Path Deform (WSM)...

[luke]

Hey all,

I'm animating a string of arrows along a path to show flow, however I don't want the arrows visible until they're on the path and also not visible once they have "left" the path (ie. >100%)... basically I'd like their visibility to start and terminate on the path... 

Any help is greatly appreciated.

[leeminardi]

Can you post a simplified model of the path and arrows?  Also, what renderer are you using? This will affect the way you can control visibility.

[luke]

Hey mate,

It's literaly an S shaped spline and the arrows are just a shelled plane and about 15 of them in a line as a single poly...

if you attach that to the spline they will start at the beginning of the spline but they will appear below the spline, I don't want to see them unless they are actually on the spline... if that makes sense... Please see attached screen shot of the arrows and spline.

I'm using Corona 6 and 3ds max... 

Thanks.

[leeminardi]

Here's another approach using Path Constraints.  It's a bit of work that may be streamlined by making all the edit to one arrow and then cloning it.  In the process outlined below I started with the arrows (teapots).

1. Check that your renderer supports a visibility track. Some do not (e.g., Arnold)
2. Create 15 arrow objects Arrow01 through Arrow15
3. Select all of them and add a visibility track and change their Rendering Control property to By Object
4. Let’s assume new arrow enters the path every 12 frames. Create a keyframe at frame 0 for all the arrows except 01 with a step function and a value of 0 on the visibility track.
5. For arrow02 set a key with a step function at frame 12 and a value of 1.
6. For arrow03 set a key with a step function at frame 24 and a value of 1.
7. For arrow04 set a key with a step function at frame 36 and a value of 1.
8. Repeat for the remaining arrows.
9. Assign a path constraint to each arrow.
10. Set the value of the % along for each arrow such that its value is 0 until they become visible
11. A similar setup for % along and visibility will be needed for the of the arrow’s run along the path.
For more information on using the visibility track see this video I made several years ago.

[luke]

Hey mate,

Thanks for the reply! Is there any chance you could save the file out as 2019?

I'd be very grateful!

Thanks @leeminardi 

[luke]

@leeminardi nevermind about the earlier max version, I've figured it out... 

it's not perfect but it'll get me through, so thanks mate! 😉

[leeminardi]

Glad to hear you got something that works for you.

I've attached a copy of the file in 2019 format.

Here's (my post #4) a different approach to animating arrows using a material .