# Arc interpolated shapes

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I tried to rebuild the awesome arc interpolated shaped tool that Ahmidou Lyazidi did in Softimage a long time ago. This is very useful to remove the linear motion of face shapes without a complex rig setup.

I just need to find a more elegant way to display the vectors, as well as isolating all the shape points from the static ones to group them.

Please have a look and let me know how I can improve this.

Here is the old video by Ahmidou
https://vimeo.com/8637260

Arc_Interpolate_101_wz.hipnc

Edited by Werner
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Little update...Now the height of the vector is driven by the distance the points travel. Much better.

Arc_Interpolate_102_wz.hipnc

Edited by Werner

WOW...

very cool

thanks!

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Thanks!

BTW.

Wouldn't it be easier to just extract positions from the eye, on the axis you are interested in, with a help of raySOP and line + CHOPS and overriding position of your points with it? It would follow the eye shape (or any shape) nicely, no matter how deformed it would be. That's old trick that was used tank tracks following the terrain.

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Thanks guys.

Yes, there are many ways to do this, but I often use this in Softimage to get rid of linear motion on shapes.

Now that it's done It is easy to plug in any object and use the added vectors.

I posted an animated gif on Sidefx...it does not want to upload here.

Edited by Werner
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I was afraid that you will say this. Last time I used CHOPs was around begin of 2011 so... hmm... lets try to figure out what was needed to get this

If you create a line between starting position of a point (lets call it A) and the position of the point where it should be after transformation (lets call it , than you got only change in path on one axis. You can drive you transformation with this, but all you get is simple linear blend. But if you resample this line and then use raySOP to cast it to the shape that is between those two points, you will get deformed line that is ideally conformed to the shape of the object, and with it you get change on second axis. Now you need to properly sample two axes of this line in CHOPS and use them to blend transformation of your point from A to B.

It's quite similar to FollowPath idea, it's just that with CHOPS you can do additional stuff on top of it. I can't promise but I will try to reproduce what I just said here. But it's a very common trick, I'm sure that many here used it before.

EDIT:

Here it is. There are two spheres there. One on OBJ level and second on SOP level. position of both is driven by deformation that I extracted from object on SOP level and exported thru CHOPS to each.

Arc_Interpolate_102_wz.hipnc

Edited by mantragora
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Thanks mantragora. So much more to learn...Chops are still unknown territory for me.

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