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lacer8

problems measuring curvature

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Hello Friends, 

I'm back again with what is surely some novice misunderstanding of the tools. Basically, I'm trying to get edge damage by measuring curvature and binding that within a point vop. However, I realized that my curvature is not being correctly measured. Instead of having the high points in the apex of the rounded edge, my gradient has the greenest result in the highest part of the rounded edge. 
Furthermore, inside the actual point vop, this 'mask' is only revealed if I use the concavity attribute... 

I don't mind calling it the wrong thing - but I'd like to have this result have the highlight on the apex of the rounded edges. Anyone know what I'm doing wrong? 

Thanks, 

p

curvature.hip

curvature_problem.jpg

curvature_problemB.jpg

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first I thought it was to do with proportion..ie one dim of your geo is muuuuuch longer than another.

diving inside you'll see they do the work on a UNIT geo, ie they matchsize down to 1x1x1 then do their voodoo then matchsize it backup.

I fooled around but no chance in hell i'm gonna try and dissect the VEX in there.

Anyway, back up, I did a simple test with transform, compare the results side by side, it's chalk and cheese. Don't ask me to explain. get the devs to do that.

curvature.jpg

vu_curvature_test.hiplc

Edited by Noobini
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Wow, thanks! That looks much better. I'll take a look and see if I can understand what you did. :)

Thanks again.

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Wow! you rotated it, and rotated it back and that fixed it? Ha ha. That's awesome, but kinda crazy. Anyway, Thanks! :)

 

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Yes, i have some trouble with this node as well, it s quite sensitive. It rotated to have a diagonal in size for the match size the sidefx measure node is using to compensate the xyz size difference, inverse the matrix transform after

 

If you dive inside the Sidefx measure_curv SOP, and turn on uniform scale in the first matchsize, it will works as you expect. A little more simple

________________________________________________________________

Vincent Thomas   (VFX and Art since 1998)
Senior Env and Lighting  artist & Houdini generalist & Creative Concepts

 http://fr.linkedin.com/in/vincentthomas

 

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