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Trigger an animation

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Can somebody please help me. I'm having this problem for a while now.
I believe its very simple, but my knowledge is still a bit limited and I can find the right information online, or in the Houdini guide.

So, I have a point moving and an animated sphere and I like trigger the animation of the sphere when the point moves through a Bounding Box.
How would I tell the sphere to animate when the point enters the bounding box? It needs to be some kind of on switch, for the sphere to animate.



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Hey Lulu01,

You can use attribute transfer node to activate the sphere . Make an attribute on the point and when it comes close to the sphere/bounding box , it will transfer the attribute value onto the sphere , and use that value to activate the animation .


A slightly more complex way to do this would be using sdf . Sdf volume has a positive value outside and a negative value inside . You can convert the sphere into a sdf volume using the isooffset node and use a volume sample to assign a value to the point inside an attributeVOP node .If you assign the value to cd(color) , you'll be able to see the color change when the point enters or exits the sdf volume . The point will have a positive value if it's outside the sphere and a negative value if inside . Now use this value to trigger something . 

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Hey ashwinsareen_3009, thx for the quick reply.
I understand what your saying, but I just don't understand how I can play the animation on demand.
I believe I need some sort of vex code or vop setup to trigger the animation, but I just know where to start looking for the right information.

If you or somebody else can find the time, I made a quick setup up. This is the last piece I need for a project, or everything will be for nothing.
A bit dramatic I konw, but it would be really nice if this can be solved.





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With a single object, the simplest solution is to move the starting keyframe for the sphere animation to the frame # where your point enters the box.




But you may want to look into triggering an animation via instancing.



Edited by Atom

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