what is parametric uv?

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Hello,

artist trying to learn math here.

what is parametric uv?

is it describing coordinates using a function with two parameters u & v?

so it nothing to do with uv's (as in texturing)?

also does prim_attribute vex function find the point nearest to the parametric position (by distance?) to get its attribute?

thanks

J
Edited by shmo - 2016年12月18日 08:48:04
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Parametric UV is intrinsic to the geometry regardless of the UV attribute, one way I use to visualize this is to use the carve sop and play with the U and V parameters.

I hope that helps.
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Some primitive have implicit UVs, like NURBS surfaces and primitive spheres. For a square NURBS patch, parametric U would be one axis and V the other. For a primitive sphere, U would be latitude and V longitude.
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hello, is there anyway I can read these intrinsic UVs of the points in a vex wrangle?

I can't seem to find any functions that returns it.
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Andr
hello, is there anyway I can read these intrinsic UVs of the points in a vex wrangle?

I can't seem to find any functions that returns it.

parametric uvs are not property of points, but primitives of certain types
so if there are more primitives attached to a single point it may be different uv per primitive so not a single uv value per point

in simpler cases like curves you can for example use xyzdist() to sample the paramteric uv on the curve the point belongs to
Edited by tamte - 2018年9月8日 14:21:54
Tomas Slancik
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your information is really very good. I get lots of useful information of parametric UV.
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thanks for clarifying !
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