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AntoineSfx

Instantiate and animate objects along curves

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I have a set of curves and one object. Can you give a starting point to end up with a sphere moving along each curve, with a time offset so that they don' t start at the same time ? I assume it' s some CHOP black magic, but I don' t really know where to start.

 

houdini.chopcopies.png.8807c04e72dfd14f4816a26f5347876e.png

houdini.chopcopies.hipnc

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Hi,

You could do that in chop, but it is not necessary, there are plenty of ways to do that, with vex / vop, sop solver, or even only in sop. Here is one proposition:

- Create a line on x (length 2 for example)

- transform it on x by 1

- resample it to max segment length 0.02 to get enough points

- copyandtransform total number 8 for example and rotate by 45 on y. It gives you a circle of lines not touching but pointing to the center

- attributevop add a 3D turbnoise to the current position (amp 0.5). Randomizes a bit the shape of th curves.

- create a foreach primitive and create Meta Import Node

     place a carve, animate the firstu from 0.99 to 0 from f0 to f75 for example. This will animate the curve over 3 secs.

     blast 0 delete non selected to keep only pt0 that is the last point is this example.

     copytopoints, plug the point in second input and a sphere in first input (scale 0.1 for this example). This will copy a sphere on each pt0 of each curve, so on the last point of each curve

     timeshift $F-5*detail("../foreach_begin1_metadata1", "iteration",0). This will offset each animation of curve by X frames.

- merge your curves from before the foreach and the output of the foreach (so the spheres moving). So that you can see the sphere moving along the curves.

 

This is a cheap method because it would become heavy in big scenes and you don't have a huge control but it works for what you want to do.

 

To build a full system, I would probably have done a vex setup using primuv or curveu attributes to make the sphere move along the curve / geo.

 

I hope that helped, have a good day!

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Posted (edited)

Thit topic has several solutions:

Resulting hip: pathAnimation.hipl
Thomas setup is much much faster but I ended up using my (can't recall the reason).

cars.thumb.PNG.0fd759cf831e97ea25c5cee44e5a5ab1.PNG

Edited by kiryha

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