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zveris

comparing point sets

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I would like to find out how can I compare two point sets, get defference vectors and apply them to the third set.In my case it is thee difference betwean two blend shapes which I would like to find out, and apply to geometry file witch is topologicaly the same (point,primitive order etc) but is different from firs two.And I need exact amoun and direction of deformation. I looked in vew builder nodes, but nothing jumped to my mind. Any sugestions?

Thx

zveris

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You could use the point SOP.

ModelDeformA goes into the first input,

ModelDeformB goes into the second,

You can add color, and for the value do

x: $TX2 - $TX

y: $TY2 - $TY

z: $TZ2 - $TZ

Then append an attribute SOP and rename Cd to Delta or something.

You could then pipe this "difference info" into another Point SOP and apply the difference there.

Or you could do it in hscript with a couple of point() expressions.

Or ....

jim.

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There's probably an easier way using the regular sops but as I'm not as familiar, here's an example use the VEX Builder.

pointdiff.zip

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I like Edward's way better. :D

I missed the part about "need[ing] exact amoun and direction of deformation." :blink:

jim.

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Hi JIM, hi Edward,

odly enough Jim's way indeed worked (to some extend, but Edwards not.

Extended explanation:

I have an animation of a characters face, it is a sequence of obj which I importiong in Houdini. It has tremendous detail, so I want to retarget the amimation for a new character, and it has the same topology(actualy it's morphed using third party tools from the scan).

So using Jims way motion comes along quite fine, exept areas where proportions are sensibly different (obvious).

Now Edwards way gives a motion for the points, but result is totaly unrecognisable motion.

thanks for input any other ideas would be highly appreciated.

Zveris

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If you turn off Use Source Normals, then it should be the same method as Jim's, no?

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The first input is the face your want to apply the difference to. I don't remember the order of the other two inputs now. I think the second input is the one you want to subtract from. I'm guessing that the inputs are just wired in wrong. But in anycase, whatever works! :)

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