Getting X and Y position from Pos + Rot transform (or a better solution?)

General TouchDesigner Discussion
1

Here’s what I’m trying to do (and please pardon my noviceness)

I want to move a circle top in a swirling motion. This could be as simple as just circling the origin, or more complex involving some wobbliness in the movement. AND I also need to access the circle’s motion as X and Y position info so I can use it for some other effects.

The way I’ve done this:
-Place noise in a transform TOP’s position param to move it off center, with some wobble.
-Use an LFO, multiplied by some noise and ranged up to 0.0 - 360.0 in the transform’s rotation param. (The transform order is set to Scale, Translate, Rotate)

I’ve not been able to extract X and Y positions from this though. I’ve tried Optical flow, which seems heavy and messy for this step and also a blob tracker, which also seems to heavy for this.

Coming from Houdini I would use Curl noise to create this circular, swirling movement. But I’m not sure how to apply that here. (I think that’s a general challenge with jumping between these apps!)

Thanks for any suggestions!!

2

Solved it I think. Just needed a few transform CHOPs to convert my position and rotation data to a matrix and then tx, ty, tz. Very handy node!

3

Hi @kokosing,

i believe a single TransformXYZ CHOP should work?

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you would use the Noise CHOP data to control the pivot parameters and the LFO/Noise data for the Rotate Z parameter and should receive the correct position. Or you use the position as the input data and then just rotate, that should do the same.

cheers
Markus

4

Oh that’s much cleaner. Thanks for that!